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

Conflicts:
	app/views/layouts/application.html.haml

Edited:
        app/helpers/application_helper.rb
        app/views/admin/domain_blocks/new.html.haml

Conflict wasn't really one, just two changes too close to one another.
Edition was to adapt the class names for themes to class names for
skins and flavours.

Also edited app/views/admin/domain_blocks/new.html.haml to strip the
duplicate admin pack inclusion thing.

app/javascript/core/admin.js

@@ -41,3 +41,10 @@ delegate(document, '.media-spoiler-hide-button', 'click', () => {
     element.click();
   });
 });
+
+delegate(document, '#domain_block_severity', 'change', ({ target }) => {
+  const rejectMediaDiv = document.querySelector('.input.with_label.domain_block_reject_media');
+  if (rejectMediaDiv) {
+    rejectMediaDiv.style.display = (target.value === 'suspend') ? 'none' : 'block';
+  }
+});