Improve metadata storage (#37)

* Updated config path to specify metadata storage path

* Removed metadata column from DB, replacing it with filepath columns

* Updated app to store compressed metadata; automatically download thumbnails

* Ensured metadata is deleted when other files are deleted

* Updated docs

* Added inets to application start so http calls work in prod

test/test_helper.exs

@@ -1,6 +1,9 @@
 Mox.defmock(YtDlpRunnerMock, for: Pinchflat.MediaClient.Backends.BackendCommandRunner)
 Application.put_env(:pinchflat, :yt_dlp_runner, YtDlpRunnerMock)
 
+Mox.defmock(HTTPClientMock, for: Pinchflat.HTTP.HTTPBehaviour)
+Application.put_env(:pinchflat, :http_client, HTTPClientMock)
+
 ExUnit.start()
 Ecto.Adapters.SQL.Sandbox.mode(Pinchflat.Repo, :manual)
 Faker.start()
@@ -8,7 +11,9 @@ Faker.start()
 ExUnit.after_suite(fn _ ->
   File.rm_rf!(Application.get_env(:pinchflat, :media_directory))
   File.rm_rf!(Application.get_env(:pinchflat, :metadata_directory))
+  File.rm_rf!(Application.get_env(:pinchflat, :tmpfile_directory))
 
   File.mkdir_p!(Application.get_env(:pinchflat, :media_directory))
   File.mkdir_p!(Application.get_env(:pinchflat, :metadata_directory))
+  File.mkdir_p!(Application.get_env(:pinchflat, :tmpfile_directory))
 end)