* Ensure that the node is synced at boot time
* Update test + add logic for checking skipped slots
* Update boot check
* Add skip_sync to config.
* Update a test so it fails
This Commit contains the following:
* Graceful shutdowns.
* Handling all incoming SSE events for reorgs, finalizations, and head.
The structure of the `BeaconClient` has drastically changed and generics are used.
