GIF permission like for the TTS.

Allow or forbid the GIFs depending of the roles and of the channels, exactly the same thing than the TTS.

GIFs are inappropriate in some cases, like a RP channel, a School server, etc.

I don't want to add a bot in order to delete each GIF sent, it will pollute the logs with many deleted messages which are actually GIF links, and the GIFs were sent anyways. So it's a problem, and bots are not the solution.

GIFs can be fun, but horrible in some cases, I think we really need this feature.