[Feature request]: Support decomposed form of `queryLog.target`

The new support for reading queryLog.target from a file (and thus a Docker secret) is great! However, because I use MariaDB for logging and queryLog.target expects a fully composed connection string, I have to maintain two secrets: one with the bare password which populates the mariadb container's MARIADB_PASSWORD_FILE environment variable, and a second which has the full connection string, with the MariaDB password copied manually in.

It would be great if queryLog.target could be told to just read the password from a file, e.g.:

queryLog:
  target:
    username: "someuser"
    password: "file:/run/secrets/mariadb_pass"
    address: "tcp(db_host_or_ip:3306)/db_name?charset=utf8mb4&parseTime=True&loc=Local"

Then I could use the same secret for both and not worry about them getting desynced.

Thanks!