Add Terms

[msaroufim]

Goal of this PR

1. If people are just interacting with the bot outside of the context of the competition that's fine!
2. But if they want to submit a ranked a submission and thus be eligible for prizes they need a leaderboard participant role
3. To get that role they need to like the Carl-Bot message which will have terms of service linked, the terms themselves mostly are there to facilitate prize distribution

This is safe with minimal friction

Can wait until we launch season 1 to merge this

[alexzhang13]

I like this over /register