## Issue Addressed
Fixes an issue identified by @remyroy whereby we were logging a recommendation to use `--eth1-endpoints` on merge-ready setups (when the execution layer was out of sync).
## Proposed Changes
I took the opportunity to clean up the other eth1-related logs, replacing "eth1" by "deposit contract" or "execution" as appropriate.
I've downgraded the severity of the `CRIT` log to `ERRO` and removed most of the recommendation text. The reason being that users lacking an execution endpoint will be informed by the new `WARN Not merge ready` log pre-Bellatrix, or the regular errors from block verification post-Bellatrix.
## Issue Addressed
Resolves#2487
## Proposed Changes
Logs a message once in every invocation of `Eth1Service::update` method if the primary endpoint is unavailable for some reason.
e.g.
```log
Aug 03 00:09:53.517 WARN Error connecting to eth1 node endpoint action: trying fallbacks, endpoint: http://localhost:8545/, service: eth1_rpc
Aug 03 00:09:56.959 INFO Fetched data from fallback fallback_number: 1, service: eth1_rpc
```
The main aim of this PR is to have an accompanying message to the "action: trying fallbacks" error message that is returned when checking the endpoint for liveness. This is mainly to indicate to the user that the fallback was live and reachable.
## Additional info
This PR is not meant to be a catch all for all cases where the primary endpoint failed. For instance, this won't log anything if the primary node was working fine during endpoint liveness checking and failed during deposit/block fetching. This is done intentionally to reduce number of logs while initial deposit/block sync and to avoid more complicated logic.
## Issue Addressed
#2282
## Proposed Changes
Reduce the outbound requests made to eth1 endpoints by caching the results from `eth_chainId` and `net_version`.
Further reduce the overall request count by increasing `auto_update_interval_millis` from `7_000` (7 seconds) to `60_000` (1 minute).
This will result in a reduction from ~2000 requests per hour to 360 requests per hour (during normal operation). A reduction of 82%.
## Additional Info
If an endpoint fails, its state is dropped from the cache and the `eth_chainId` and `net_version` calls will be made for that endpoint again during the regular update cycle (once per minute) until it is back online.
Co-authored-by: Paul Hauner <paul@paulhauner.com>
## Issue Addressed
part of #1883
## Proposed Changes
Adds a new cli argument `--eth1-endpoints` that can be used instead of `--eth1-endpoint` to specify a comma-separated list of endpoints. If the first endpoint returns an error for some request the other endpoints are tried in the given order.
## Additional Info
Currently if the first endpoint fails the fallbacks are used silently (except for `try_fallback_test_endpoint` that is used in `do_update` which logs a `WARN` for each endpoint that is not reachable). A question is if we should add more logs so that the user gets warned if his main endpoint is for example just slow and sometimes hits timeouts.
