Database migrations for Parallel persist AuditEvent#target_details

What does this MR do?

This extracts database migrations from !36567 (merged), so those can be merged individually.

This might help us to get the database-side of this in, before we merge the partitioning migration !36298 (merged).

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content