[Feature Request] Delete Conversation #73

The option to "Delete" (or maybe Erase might be a better word?) a conversation in addition to "Mark as Unread", "Mute", and "Block".

This would be for users you don't want to mute or block. Reasons would be someone you don't talk to often but want to declutter your app (but still want them to be able to reach you or vice versa). Also, to simply delete a sensitive conversation you don't want hanging around locally on your device.