Merge commit '1e3b19230a48174acf524cf1a9f5a498e220ea7d' into glitch-soc/merge-upstream

Conflicts:
- `app/models/account.rb`:
  Upstream added new validations close to lines on which glitch-soc had
  modified validations to handle custom limits set through environment
  variables.
  Ported upstream changes.
- `config/initializers/content_security_policy.rb`:
  Upstream added `AZURE_ALIAS_HOST`. Glitch-soc's version of the file is
  completely different.
  Added `AZURE_ALIAS_HOST` to our version of the file.

app/javascript/mastodon/features/ui/index.jsx

@@ -184,6 +184,7 @@ class SwitchingColumnsArea extends PureComponent {
 
           {singleColumn ? <Redirect from='/deck' to='/home' exact /> : null}
           {singleColumn && pathName.startsWith('/deck/') ? <Redirect from={pathName} to={pathName.slice(5)} /> : null}
+          {!singleColumn && pathName === '/getting-started' ? <Redirect from='/getting-started' to='/deck/getting-started' exact /> : null}
 
           <WrappedRoute path='/getting-started' component={GettingStarted} content={children} />
           <WrappedRoute path='/keyboard-shortcuts' component={KeyboardShortcuts} content={children} />