* fix several memory leaks due to temporaries not being reset during
init
* avoid massive main() function with lots of stuff in it
* disable nim-prompt (unused)
* reuse validator pool instance in eth2_processor
* style cleanup
* Create CLI tool for slashing export
* Use SQLite as a DB instead of a KV-store
* Keeps v1 and v2 DBs around
* Uses the same schema as Lighthouse v1.1.0
* Passes all interchange tests + skeleton of finalization pruning
* Removes tests that would violate v5 / minimal slashing DB and MinSlot rules
* Migration tool added using low-watermark scheme for faster migration of large number of validators
* performance fixes
* don't mark tree cache as dirty on read-only List accesses
* store only blob in memory for keys and signatures, parse blob lazily
* compare public keys by blob instead of parsing / converting to raw
* compare Eth2Digest using non-constant-time comparison
* avoid some unnecessary validator copying
This branch will in particular speed up deposit processing which has
been slowing down block replay.
Pre (mainnet, 1600 blocks):
```
All time are ms
Average, StdDev, Min, Max, Samples, Test
Validation is turned off meaning that no BLS operations are performed
3450.269, 0.000, 3450.269, 3450.269, 1, Initialize DB
0.417, 0.822, 0.036, 21.098, 1400, Load block from database
16.521, 0.000, 16.521, 16.521, 1, Load state from database
27.906, 50.846, 8.104, 1507.633, 1350, Apply block
52.617, 37.029, 20.640, 135.938, 50, Apply epoch block
```
Post:
```
3502.715, 0.000, 3502.715, 3502.715, 1, Initialize DB
0.080, 0.560, 0.035, 21.015, 1400, Load block from database
17.595, 0.000, 17.595, 17.595, 1, Load state from database
15.706, 11.028, 8.300, 107.537, 1350, Apply block
33.217, 12.622, 17.331, 60.580, 50, Apply epoch block
```
* more perf fixes
* load EpochRef cache into StateCache more aggressively
* point out security concern with public key cache
* reuse proposer index from state when processing block
* avoid genericAssign in a few more places
* don't parse key when signature is unparseable
* fix `==` overload for Eth2Digest
* preallocate validator list when getting active validators
* speed up proposer index calculation a little bit
* reuse cache when replaying blocks in ncli_db
* avoid a few more copying loops
```
Average, StdDev, Min, Max, Samples, Test
Validation is turned off meaning that no BLS operations are performed
3279.158, 0.000, 3279.158, 3279.158, 1, Initialize DB
0.072, 0.357, 0.035, 13.400, 1400, Load block from database
17.295, 0.000, 17.295, 17.295, 1, Load state from database
5.918, 9.896, 0.198, 98.028, 1350, Apply block
15.888, 10.951, 7.902, 39.535, 50, Apply epoch block
0.000, 0.000, 0.000, 0.000, 0, Database block store
```
* clear full balance cache before processing rewards and penalties
```
All time are ms
Average, StdDev, Min, Max, Samples, Test
Validation is turned off meaning that no BLS operations are performed
3947.901, 0.000, 3947.901, 3947.901, 1, Initialize DB
0.124, 0.506, 0.026, 202.370, 363345, Load block from database
97.614, 0.000, 97.614, 97.614, 1, Load state from database
0.186, 0.188, 0.012, 99.561, 357262, Advance slot, non-epoch
14.161, 5.966, 1.099, 395.511, 11524, Advance slot, epoch
1.372, 4.170, 0.017, 276.401, 363345, Apply block, no slot processing
0.000, 0.000, 0.000, 0.000, 0, Database block store
```
* fix subnet calculation in RPC and insert broadcast attestations into node's pool
* unify codepaths to ensure only mostly-checked-to-be-valid attestations enter the pool, even from node's own broadcasts
* update attestation pool tests for new validateAttestation param
* detect already-aggregate-voted condition before attestation pool; add is_aggregator tests
* replace pair of attestation-per-epoch tracking lists with single list and remove Option use
* fix attestation condition
* use safer type conversions; add more is_aggregator tests
* don't lag aggregated attestations by a slot
* don't use aggregation topic at all
* use aggregates again, but with aggressively low ATTESTATION_PROPAGATION_SLOT_RANGE; seems to hold on to LH 1.0 nodes
* clean up scaffolding and double ATTESTATION_PROPAGATION_SLOT_RANGE to 16
* increase ATTESTATION_PROPAGATION_SLOT_RANGE to 24
* increase ATTESTATION_PROPAGATION_SLOT_RANGE to 28 and isolate in only used function due to customization; remove TRAILING_DISTANCE machinery
* Handle some web3 timeouts better
* Add support for developer .env files
* Eth1 improvements; Mainnet genesis state
Notable changes:
* The deposits table have been removed from the database. The client
will no longer process all deposits on start-up.
* The network metadata now includes a "state snapshot" of the deposit
contract. This allows the client to skip syncing deposits made prior
to the snapshot (i.e. genesis). Suitable metadata added for Pyrmont
and Mainnet.
* The Eth1 monitor won't be started unless there are validators attached
to the node.
* The genesis detection code is now optional and disabled by default
* Bugfix: The client should not produce blocks that will fail validation
when it hasn't downloaded the latest deposits yet
* Bugfix: Work around the database corruption affecting Pyrmont nodes
* Remove metadata for Toledo and Medalla
* log when database is loading (to avoid confusion)
* generate network keys later during startup
* fix quarantine not scheduling chain of parents for download and
increase size to one epoch
* log validator count, enr and peerid more clearly on startup
* misc memory and perf fixes
* use EpochRef for attestation aggregation
* compress effective balances in memory (medalla unfinalized: 4gb ->
1gb)
* avoid hitting db when rewinding to head or clearance state
* avoid hitting db when blocks can be applied to in-memory state -
speeds up startup considerably
* avoid storing epochref in fork choice
* simplify and speed up beacon block creation flow - avoids state reload
thanks to head rewind optimization
* iterator-based committee and attestation participation help avoid lots
of small memory allocations throughout epoch transition (40% speedup on
epoch processing, for example during startup)
* add constant for threshold
* in exit pool, filter out already-packaged messages; bundle remaining messages into beaconblocks
* filter messages at block construction time
* allow adding up to intended capacity of buffers, beyond per-block limits
* document rationale/design for filtering mechanism