flatpak_repo plugin

flatpak repository element

A ScriptElement implementation for exporting a flatpak repository from a set of `flatpak_image`s.

The flatpak_repo default configuration:
  # elements (from the build dependencies) that should be staged in /
  environment: []
  # refs of which a copy is to be made using flatpak build-commit-from
  # a list of mappings containing keys `src` and `dest`
  copy-refs: []
  # the mode of the ostree repo (one of archive, bare, bare-user, bare-user-only)
  repo-mode: 'archive'
  arch: '%{arch}'
  branch: '%{branch}'