Add support for posting freeform reactions on Android

[kittykat]

What would you like to do?

I would like to be able to send freeform reactions on Android

Why would you like to do it?

• MSC2677 supports reactions with long keys, i.e. text reactions
• This feature is already available through other apps and our users can see those reactions
• It is already possible to send freeform reactions through bots from Element, so at the moment the feature exists but is obscure
• Element users can already "+1" a freeform reaction on any platform by clicking it

How would you like to achieve it?

• By being able to compose a freeform reaction on Android
• Being able to view long reactions in a user friendly way (I can't see any upper limit set by the MSC)
• Be able to report reactions to moderators
• Remove reactions as a moderator/admin user in a room
• Seealso this comment from Jim on moderation