feat: add support for databases enforcing strict data integrity through PKs. Fixes #13611

[radusora]

Fixes #13611

Motivation

As outlined in #13611, certain database systems depend on the presence of primary keys to support replication and ensure data integrity. For instance, Percona XtraDB’s pxc_strict_mode enforces this requirement.

Modifications

The schema_history table lacked a primary key, and adding one through existing migrations was not feasible because earlier migrations would fail in the environments described above. To address this, the table creation statement for schema_history was updated to include a primary key. Additionally, code was added to check for the presence of the primary key in existing installations and add it if it is missing (making sure the changes are idempotent).

Verification

The changes were tested in a local development environment using both MySQL and Postgres, with scenarios including deploying a new cluster and modifying an existing one. Furthermore, a similar test was conducted with a Percona XtraDB cluster deployed via the Percona Operator.

Additionally, I verified that the query against information_schema.table_constraints is supported by all the databases we support, and that default permissions should suffice for accessing it.

[MasonM]

Thanks! I tested this locally with both MySQL 8.4.4 and PostgreSQL 12.22