storage manager: remove fog backend.

Remove in favor of rclone.

app/logical/storage_manager/cloud.rb

@@ -1,32 +0,0 @@
-class StorageManager::Cloud < StorageManager
-  attr_reader :bucket, :client, :fog_options
-
-  def initialize(bucket, client: nil, fog_options: {}, **options)
-    @bucket = bucket
-    @fog_options = fog_options
-    @client = client || Fog::Storage.new(**fog_options)
-    super(**options)
-  end
-
-  def store(io, path)
-    io.rewind # XXX caller should be responsible for this.
-    data = io.read
-    client.put_object(bucket, key(path), data)
-  end
-
-  def delete(path)
-    client.delete_object(bucket, key(path))
-  end
-
-  def open(path)
-    file = Tempfile.new(binmode: true)
-    response = client.get_object(bucket, key(path))
-    file.write(response.body)
-    file.rewind
-    file
-  end
-
-  def key(path)
-    path.delete_prefix("/")
-  end
-end