Move DB Bucket definitions to consumer packages

[wemeetagain]

Is your feature request related to a problem? Please describe.

DB Bucket entries are all defined in the db package. Some of these entries are used in the beacon node (lodestar package), some are used in the validator (validator package).
The db package should really only be used to define the abstract db logic, and doesn't need to know which buckets exist for all downstream db consumers.

Describe the solution you'd like

Move bucket entries to the lodestar and validator packages.

Describe alternatives you've considered

Leave as is

Additional context

See https://github.com/ChainSafe/lodestar/blob/master/packages/db/src/schema.ts#L8-L70

[dapplion]

Sounds good, we can add a test in the lodestar and validator repos to ensure the Buckets don't overlap

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.