Resolve "Add a "Replace current playlist" option"

Related issue: #761 (closed)

This Merge Request includes:

• A changelog fragment (cf https://docs.funkwhale.audio/contributing.html#changelog-management)

This MR adds the ability to replace the queue's current contents with the selected album/track/playlist similar to how this is handled in players such as Clementine. This is mostly used to keep queues neat without having to click the "clear" icon each time.

Replace