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

Conflicts:
- `README.md`:
  Minor upstream change, our README is completely different.
  Kept ours.
- `lib/tasks/assets.rake`:
  glitch-soc has extra code to deal with its theming system,
  upstream changed a line that exists in glitch-soc.
  Applied upstream changes.

app/models/form/admin_settings.rb

@@ -40,6 +40,7 @@ class Form::AdminSettings
     media_cache_retention_period
     content_cache_retention_period
     backups_retention_period
+    status_page_url
   ).freeze
 
   INTEGER_KEYS = %i(
@@ -85,6 +86,7 @@ class Form::AdminSettings
   validates :show_domain_blocks_rationale, inclusion: { in: %w(disabled users all) }, if: -> { defined?(@show_domain_blocks_rationale) }
   validates :media_cache_retention_period, :content_cache_retention_period, :backups_retention_period, numericality: { only_integer: true }, allow_blank: true, if: -> { defined?(@media_cache_retention_period) || defined?(@content_cache_retention_period) || defined?(@backups_retention_period) }
   validates :site_short_description, length: { maximum: 200 }, if: -> { defined?(@site_short_description) }
+  validates :status_page_url, url: true
   validate :validate_site_uploads
 
   KEYS.each do |key|