Media downloading indexing options (round 2) (#14)

* Adds options + option builder + metadata parsing for media thumbnails

* Added release-type options to media profile; built option parser for indexing operations

* Added new media_profile options to creation form; made show helper for rendering database items

* Added options for downloading/embedding metadata

* Adds option on sources to not download media (index only)

* reformatted docs

.gitignore

@@ -39,3 +39,4 @@ npm-debug.log
 /.elixir_ls
 .env
 .DS_Store
+scratchpad.md