* prepare multiplexing support for database plugins
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.
* feat: add redshift database plugin * build: update vendored libraries * docs: add reference doc for redshift variant of the database secrets engine * feat: set middlewear type name for better metrics naming (#8346) Co-authored-by: Becca Petrin <beccapetrin@gmail.com>