* Fix REST some rest call signatures and implement a simple API benchmark tool
* Implement #3129 (Optimized history traversals in the REST API)
Other notable changes:
The `updateStateData` procedure in the `blockchain_dag.nim` module is
optimized to not rewind down to the last snapshot state saved in the
database if the supplied input state can be used as a starting point
instead.
* Disallow await in withStateForBlockSlot
* Support starting from altair
* hide `finalized-checkpoint-` - they are incomplete and usage may cause
crashes
* remove genesis detection code (broken, obsolete)
* enable starting ChainDAG from altair checkpoints - this is a
prerequisite for checkpoint sync (TODO: backfill)
* tighten checkpoint state conditions
* show error when starting from checkpoint with existing database (not
supported)
* print rest-compatible JSON in ncli/state_sim
* altair/merge support in ncli
* more altair/merge support in ncli_db
* pre-load header to speed up loading
* fix forked block decoding
* Reduce the logging-related breaking changes
* Don't disable the stdout log when the `--log-file` option is used
* Rename `--log-stdout` to `--log-format` and hide it
* Deprecate the `--log-file` option
* Logging and startup improvements
Color support for released binaries!
* startup scripts no longer log to file by default - this only affects
source builds - released binaries don't support file logging
* add --log-stdout option to control logging to stdout (colors, json)
* detect tty:s vs redirected logs and log accordingly
* add option to disable log colors at runtime
* simplify several "common" logs, showing the most important information
earlier and more clearly
* remove line numbers / file information / tid - these take up space and
are of little use to end users
* still enabled in debug builds and tools
* remove `testnet_servers_image` compile-time option
* server images, released binaries and compile-from-source now offer
the same behaviour and features
* fixes https://github.com/status-im/nimbus-eth2/issues/2326
* fixes https://github.com/status-im/nimbus-eth2/issues/1794
* remove instanteneous block speed from sync message, keeping only
average
before:
```
INF 2021-10-28 16:45:59.000+02:00 Slot start topics="beacnde" tid=386429 file=nimbus_beacon_node.nim:884 lastSlot=2384027 wallSlot=2384028 delay=461us84ns peers=0 head=75a10ee5:3348 headEpoch=104 finalized=cd6804ba:3264 finalizedEpoch=102 sync="wwwwwwwwww:0:0.0000:0.0000:00h00m (3348)"
INF 2021-10-28 16:45:59.046+02:00 Slot end topics="beacnde" tid=386429 file=nimbus_beacon_node.nim:821 slot=2384028 nextSlot=2384029 head=75a10ee5:3348 headEpoch=104 finalizedHead=cd6804ba:3264 finalizedEpoch=102 nextAttestationSlot=-1 nextProposalSlot=-1 nextActionWait=n/a
```
after:
```
INF 2021-10-28 22:43:23.033+02:00 Slot start topics="beacnde" slot=2385815 epoch=74556 sync="DDPDDPUDDD:10:5.2258:01h19m (2361088)" peers=37 head=eacd2dae:2361096 finalized=73782:a4751487 delay=33ms687us715ns
INF 2021-10-28 22:43:23.291+02:00 Slot end topics="beacnde" slot=2385815 nextActionWait=n/a nextAttestationSlot=-1 nextProposalSlot=-1 head=eacd2dae:2361096
```
* fix comment
* documentation updates
* mention `--log-file` may be deprecated in the future
* update various docs
* add doppelganger detection explanation to FAQ and link to Joe's guide from our Pi guide
* Edit CLI options page
* cp
* merge with ith unstable
* prysm migration guide: add steps until import slashing db
* update systemd
* update troubleshooting
* update pi guide
* metrics: replace winners with community
* update migration guide
* cp
* progress with guides, various edits
* Add default port info
* Add default port info
* Edit CLI and docs to reflect 9000 port
* Apply suggestions from code review
Co-authored-by: Jacek Sieka <arnetheduck@gmail.com>
