This also temporarily disables couchbase, elasticsearch, and
mongodbatlas because the `Serve` function needs to change signatures
and those plugins are vendored in from external repos, causing problems
when building.
* fix: rotate root credentials for database plugins using WAL
* test: adds a test for WAL rollback logic
* fix: progress on wal rollback
* docs: updates some comments
* docs: updates some comments
* test: adds additional test coverage for WAL rollback
* chore: remove unneeded log
* style: error handling, imports, signature line wraps
* fix: always close db plugin connection
