* add custom css account property + db func to fetch
* allow account to get/set custom css
* serve custom css for an account
* go fmt
* use monospace for customcss, add link
* add custom css to account cache
* fix broken field
* add custom css docs to user guide
* add `accounts-allow-custom-css` config flag
* add allow custom css to /api/v1/instance response
* only show/set custom css if allowed to do so
* only set/serve custom account css if enabled
* update swagger docs
* chain promise
* make bool a bit clearer
* use cache for GetAccountCustomCSSByUsername
* update templates
* start reworking api error handling
* update template
* return AP status at web endpoint if negotiated
* start making api error handling much more consistent
* update account endpoints to new error handling
* use new api error handling in admin endpoints
* go fmt ./...
* use api error logic in app
* use generic error handling in auth
* don't export generic error handler
* don't defer clearing session
* user nicer error handling on oidc callback handler
* tidy up the sign in handler
* tidy up the token handler
* use nicer error handling in blocksget
* auth emojis endpoint
* fix up remaining api endpoints
* fix whoopsie during login flow
* regenerate swagger docs
* change http error logging to debug