Merge branch 'master' into glitch-soc/merge-upstream

Conflicts:
- `Gemfile.lock`:
  Not a real conflict, just a glitch-soc-only dependency too close to a
  dependency that got updated upstream. Updated as well.
- `app/models/status.rb`:
  Not a real conflict, just a change too close to glitch-soc-changed code
  for optionally showing boosts in public timelines.
  Applied upstream changes.
- `app/views/layouts/application.html.haml`:
  Upstream a new, static CSS file, conflict due to glitch-soc's theming
  system, include the file regardless of the theme.
- `config/initializers/content_security_policy.rb`:
  Upstream dropped 'unsafe-inline' from the 'style-src' directive, but
  both files are very different. Removed 'unsafe-inline' as well.

app/views/settings/identity_proofs/_proof.html.haml

@@ -18,3 +18,4 @@
 
   %td
     = table_link_to 'external-link', t('identity_proofs.view_proof'), proof.badge.proof_url if proof.badge.proof_url
+    = table_link_to 'trash', t('identity_proofs.remove'), settings_identity_proof_path(proof), method: :delete, data: { confirm: t('admin.accounts.are_you_sure') }