Move mod contact form to the bot

[nickmccurdy]

We currently have a Contact page but it seems like more spammers are discovering it than legitimate users. Since Discord seems to have better spam protection than Netlify, moving anonymous contacting to Discord should give us less noise. This would be distinct from modmail, which creates non-anonymous private channels, rather than submitting anonymous one-off messages. Additionally most users seem to stick to contact methods within Discord without going to the site, so it should make the contact method easier to discover.

We appear to have at least one user who is intentionally abusing the contact form. As a result we may need a way to ban certain IDs, either by not actually making the form anonymous or using some sort of hash or uid so we can ban repeat offenders without having their Discord handle stored.