* Accept finalised hash from RPC with the canon header as well
* Reorg internal sync descriptor(s)
details:
Update target from RPC to provide the `consensus header` as well as
the `finalised` block number
why:
Prepare for using `importBlock()` instead of `persistBlocks()`
* Cosmetic updates
details:
+ Collect all pretty printers in `helpers.nim`
+ Remove unused return codes from function prototype
* Use `importBlock()` + `forkChoice()` rather than `persistBlocks()`
* Update logging and metrics
* Update docu
* Remove `--sync-mode` option from nimbus config
why:
Currently there is only one sync mode available.
* Rename `flare` -> `beacon`, but not base module folder and nim source
why:
The name `flare` was used do designate an alternative `beacon` mode that.
Leaving the base folder and source as-is for a moment, makes it easier
to read change diffs.
* Rename `flare` base module folder and nim source: `flare` -> `beacon`