feat(zk_inception): Offer a standalone database initialization command

[doyleish]

What ❔

This change brings database init, migration, into it's own subcommand in zk_inception chain database. It attempts to be backwards compatible, still offering the ability to be run via ecosystem init, or chain init, by introducing a layer of inheritance in the genesis and database arguments.

Also adds genesis skip flags to {ecosystem, chain} init to support the below workflow

Why ❔

The overall goal of this change is to support running chain init in smaller pieces, at different times. My use-case roughly looks like:

- ecosystem create
- l1 contracts deployed
* stand up some infra like db *
- init db
* stand up some runtime for server i.e. k8s *
- server --genesis

Checklist

• PR title corresponds to the body of PR (we generate changelog entries from PRs).
• Tests for the changes have been added / updated.
• Documentation comments have been added / updated.
• Code has been formatted via zk fmt and zk lint.

[sanekmelnikov]

Thank you very much!
We've took these ideas into #2946
Please take a look and see if that's working for you :)