Fix the `/eth/v1/beacon/deposit_snapshot` API to produce proper EIP-4881
compatible `DepositTreeSnapshot` responses. The endpoint used to expose
a Nimbus-specific database internal format.
Also fix trusted node sync to consume properly formatted EIP-4881 data
with `--with-deposit-snapshot`, and `--finalized-deposit-tree-snapshot`
beacon node launch option to use the EIP-4881 data. Further ensure that
`ncli_testnet` produces EIP-4881 formatted data for interoperability.
EIP-4881 was never correctly implemented, the `DepositTreeSnapshot`
structure has nothing to do with its actual definition. Reflect that
by renaming the type to a Nimbus-specific `DepositContractSnapshot`,
so that an actual EIP-4881 implementation can use the correct names.
- https://eips.ethereum.org/EIPS/eip-4881#specification
Notably, `DepositTreeSnapshot` contains a compressed sequence in
`finalized`, only containing the minimally required intermediate roots.
That also explains the incorrect REST response reported in #5508.
The non-canonical representation was introduced in #4303 and is also
persisted in the database. We'll have to maintain it for a while.
Other changes:
* More optimal search for TTD block.
* Add timeouts to all REST requests during trusted node sync.
Fixes#4037
* Removed support for storing a deposit snapshot in the network
metadata.
Etan Kissling
Jacek Sieka
tersec
zah