This commit adds a new index and migration to the DBRP service for
retrieving all database and retention policy mappings for a single
organization.
This change was required to resolve an invalid assumption of the DBRP
service, which relied on a prefix match of the byOrgAndDatabase kv.Index
when performing search operations by organization ID only.
Closes#20096
* refactor: migrator and introduce Store.(Create|Delete)Bucket
feat: kvmigration internal utility to create / managing kv store migrations
fix: ensure migrations applied in all test cases
* chore: update kv and migration documentation
Daniel Moran
Stuart Carnie
George
Gavin Cabbage
Gianluca Arbezzano