feat: Bootstrap metastore for wal segments

[cyriltovena]

What this PR does / why we need it:

This adds a new component metastore that is using raft for reliability and index the last 15m of wal segment ID.

This is very hacky and experimental to move forward with querying the wal segment without listing them all. This is going to change a lot over time.

TODO:

• Needs to wire that up in the write path now.

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
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[grobinson-grafana]

Looks OK to me, however I didn't look at the metastore code in depth, just at the integration with ingester-rf1. If you would like a more in-depth review of the metastore code please ask!