Update contact methods

[skullbunnygalaxy]

Here are some potential issues with current contact methods:

1. IRC channel does not seem to exist anymore.
2. ntlk does not exist anymore on twitter.
3. WhyComputer on twitter not updated since 2015. Is it still being monitored?

Suggestions:

• Much of twitter has left for Mastodon. Perhaps replace twitter contacts with updated Mastodon contacts? At the very least, remove the non-active twitter link.
• Replace IRC with Discord?