Truncate Liquibase changelogs prior to GA release

[nscuro]

Current Behavior

The Liquibase changelog has accumulated a lot of (verbose) changesets, and will continue to do so until we reach GA status.

Proposed Behavior

To make maintenance easier past GA, truncate all existing changesets into a single one.

Care must be taken to ensure that instances that ran all previous changesets will continue to work as if the truncation never happened.

Checklist

• I have read and understand the contributing guidelines
• I have checked the existing issues for whether this enhancement was already requested

[nscuro]

Obviously blocked until shortly before release.