Add a command for reindexing a system broken by an os upgrade

Several self-managed instances have seen index corruption when upgrading their postgresql database to a new operating system, changing the underlying index collation provided by libc. This can happen even when the name of the collation stays the same. These instances see incorrect results from queries involving text-based indexes, and possibly silent of unique index constraints.

As a remediation of the error produced in Automatically detect changes in postgres collation (gitlab#370622 - closed), we want to provide an omnibus command to reindex possibly corrupted indexes.

Deliverables

• An omnibus command is added to re-index possibly corrupted indexes