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.

lib/mastodon/media_cli.rb

@@ -144,7 +144,14 @@ module Mastodon
           begin
             size = File.size(path)
 
-            File.delete(path) unless options[:dry_run]
+            unless options[:dry_run]
+              File.delete(path)
+              begin
+                FileUtils.rmdir(File.dirname(path), parents: true)
+              rescue Errno::ENOTEMPTY
+                # OK
+              end
+            end
 
             reclaimed_bytes += size
             removed += 1

lib/mastodon/upgrade_cli.rb

@@ -121,7 +121,7 @@ module Mastodon
             FileUtils.mv(previous_path, upgraded_path)
 
             begin
-              FileUtils.rmdir(previous_path, parents: true)
+              FileUtils.rmdir(File.dirname(previous_path), parents: true)
             rescue Errno::ENOTEMPTY
               # OK
             end
@@ -131,7 +131,7 @@ module Mastodon
 
           unless dry_run?
             begin
-              FileUtils.rmdir(upgraded_path, parents: true)
+              FileUtils.rmdir(File.dirname(upgraded_path), parents: true)
             rescue Errno::ENOTEMPTY
               # OK
             end