Add the option to remove a message

[Migarve55]

It would be nice if we could delete our own messages.

Conditions:

• [ ] An "Are you sure?" prompt should be displayed.
• [x] The delete option should be only available for our own messages.
• [x] The feed should refresh correctly.

[Migarve55]

I think that the best way to this is to do two different things:

• Add a context menu to our messages
• Add a button to each message

Both need to check that your message, is in fact, yours.