Add opt-in for random headpat emojis

[MysticMia]

Some people dislike the automatic headpats. It'll be removed until there's an opt-in method. Could possibly be combined with other opt-in things to create more awareness for it. Then once you know to opt into things, there will be a large list of options.

Idea:
Disable all(?) Rina commands and features until you make a selection from a large list. This will typically just be 'everything', unless people would like to specify their preferences.

It is somewhat connected with #17 but for users/members instead of guilds. Requires new database design though, I suppose. And reworking all the checks.