Low hanging fruit in settings page

[BenKellySoftware]

There's some stuff in the settings page we can get implemented pretty easy:

• [x] Change username
• [x] Change pin
• [x] Submit an issue (via a google doc redirect)
• [x] Join us on Discord
• [x] Follow our socials (Fb, twitter, others?)
• [x] App version
• [x] Security info (you blockchain id? what else should be here?)
• [x] Review onboarding

And hide everything else that's not hide (with a feature flag)

[KipCrossing]

This also being worked on in #208