Revise display on artist commentary versions index

- All text fields are now shown in their non-rendered form
-- This allows changes to be highlighted with the diff builder
-- The different fields were labeled and separated for easier discernment
-- Fields are only shown if they have text in either the current or previous versions
- Various changes are also verbalized for easier discovery
- The date and the user columns were combined
-- This is more in line with other indexes, plus it saves on space
- The revert listing was changed to use a thumbnail instead of post ID links
-- This makes it more in line with the post versions index

app/javascript/src/styles/specific/artist_commentary_versions.scss

@@ -0,0 +1,15 @@
+div#c-artist-commentary-versions {
+  #a-index {
+    div.commentary-body-section {
+      padding: 0.5em;
+      margin-bottom: 0.5em;
+      border: var(--footer-border);
+    }
+
+    td.original-column,
+    td.translated-column {
+      padding-top: 0.5em;
+      vertical-align: top;
+    }
+  }
+}