Database - Default to building plugin backend from dockerfiles

[TrainDoctor]

Required before moving to full-release of Plugin Loader V2.

An example Dockerfile will be located in the template repo. See SteamDeckHomebrew/decky-plugin-template/issues/1

After the dockerfile from the plugin is ran by the CI and the binaries are placed into their a standardized directory, these binaries will be included during the zipping step which are then sent to the store in the CD steps.