[Media] Fix issues with database file storage

Fixed file quota as well.

There can be more than one file for the same filehash IF the url are different.

Possible states:
  - A file with no url and with filename is a local file.
  - A file with an url but no filename is a remote file that wasn't fetched,
    not even the thumbnail.
  - A file with an url and filename is a fetched remote file (maybe just a
    thumbnail of it).
  - A file with no filename nor url is a redirect.

Routes:
  Given these states, updated routes so that an attachment can only be
  retrieved by id and a file by filehash.

Major API changes:
  File::getByHash now returns a yield of files

Major UI changes:
  - Now remote non stored files are presented.
  - /view became preferred
  - Redirects to remote originals are preferred.

Many other minor bug fixes...

plugins/StoreRemoteMedia/StoreRemoteMediaPlugin.php

@@ -138,6 +138,7 @@ class StoreRemoteMediaPlugin extends Plugin
         try {
             // Exception will be thrown before $file is set to anything, so old $file value will be kept
             $file = File::getByHash($filehash);
+            $file->fetch();
 
             //FIXME: Add some code so we don't have to store duplicate File rows for same hash files.
         } catch (NoResultException $e) {