* op-supervisor: Introduce head tracker

* op-supervisor: Move log db to subpackage of db.

* op-supervisor: Route all updates through a common db that can track heads

* op-supervisor: Remove unused error.

* op-supervisor: Remove operations - it fits into a later PR.

* op-supervisor: Fix semgrep

* op-supervisor: Move resuming databases into ChainsDB so it can later update the chain heads too.

* op-supervisor: Move TruncatedHash and ExecutingMessage out of db package

* op-supervisor: Introduce EntryIdx type

Will make it clear when a value is a block number vs a db entry index when adding head tracking.

Add tests for finding the block to start from.

Executing messages aren't extracted yet but basic log information is hashed and written.

* finish TODO(optimism#11023)

* revert GetLogBlockNum() && use ClosestBlockInfo

* catch error

* rewind

* gofmt -w -s .

* op-supervisor: Remove unused import.

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Co-authored-by: Adrian Sutton <adrian@oplabs.co>

* op-supervisor: Create clients and monitor chain heads for each L2 chain

* op-supervisor: Remove rpc url from log message

* op-supervisor: Update tickets in TODOs

* op-supervisor: initial service draft

* supervisor: Fix log capitalization

* op-supervisor: fix mockrun flag

* op-supervisor: CLI tests

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Co-authored-by: Adrian Sutton <adrian@oplabs.co>