Add ability to add / save 2-factor auth

[dessalines]

Pre-Flight checklist

• Did you check to see if this issue already exists?
• This is a single feature request. (Do not put multiple feature requests in one issue)
• This is not a question or discussion. (Use https://lemmy.ml/c/jerboa for that)

Describe The Feature Request Below

This is a part of your local user settings. It can already be set up through lemmy-ui, but needs to be added to jerboa.