Delete processed data of no-longer-current pipeline versions after upgrade to save on storage

[corneliusroemer]

After we bump the current processing pipeline version, processed data of previous pipeline versions doesn't serve a purpose anymore. We should just delete it to not accrue waste.

No longer purposeful processed data is the main source of db storage at the moment in production pathoplexus (already noticeably slowing down cloning from prod to staging).

Proposed feature:

• As part of bumping the processing pipeline version, after successfully having bumped the version, delete all outdated rows.

See this comment for an analysis of db storage: #3232 (comment)

The alternative is manually deleting old versions but I don't see reason for doing this manually when we can do it automatically.

[chaoran-chen]

I wonder whether we should keep current - 1 around just in case one would like to reverse and delete older ones.