[Enhancement] Allow redownloading of files for existing media items (#239)

* Added ability to specify overwrite behaviour when downloading media

* Added helper for redownloading media items

* renamed media redownload worker to disambiguate it from similarly named methods

* Added new redownload option to source actions dropdown

* Refactored MediaQuery to use a __using__ macro

* docs

lib/pinchflat_web/controllers/pages/page_controller.ex

@@ -1,9 +1,9 @@
 defmodule PinchflatWeb.Pages.PageController do
   use PinchflatWeb, :controller
+  use Pinchflat.Media.MediaQuery
 
   alias Pinchflat.Repo
   alias Pinchflat.Sources.Source
-  alias Pinchflat.Media.MediaQuery
   alias Pinchflat.Profiles.MediaProfile
 
   def home(conn, params) do