Is your feature request related to a problem? Please describe.
A good way for me to separate the database and other application is to use a Unix-Socket while also avoiding Docker networking complexities. Currently, it seems there's no straightforward way to configure the MariaDB connection in RomM to use a Unix socket when using the mariadb+mariadbconnector (also the case for mysql+mysqlconnector) driver.
From the available DB driver currently only postgresql+psycopg allows a unix-socket with the current code.

Describe the solution you'd like
The mariadb+mariadbconnector (and mysql+mysqlconnector) driver requires a specific unix_socket parameter in the connection URL to connect via Unix socket, but the current configuration only supports specifying a host, which is interpreted as a hostname rather than a socket path. Ideally, there should be support for a dedicated configuration option (e.g., unix_socket) or logic to detect and translate socket paths appropriately.

Describe alternatives you've considered
Allowing a fully custom database URL string as a configuration option could provide flexibility to cover Unix socket connections and other advanced setups without changing the standard connection interface.

Additional context
Supporting Unix sockets for all databases could simplify local container setups by removing dependency on network configuration.