post events: show post-related mod actions on post event page.

Show the following actions on the post events page:

* Post bans and unbans
* Post deletions and undeletions
* Thumbnail regenerations and IQDB regenerations
* Favorites moves
* Rating locks and unlocks
* Note locks and unlocks

Fixes #3825: Events/Moderation page for each post should show eventual ban actions

db/views/post_events_v02.sql

@@ -0,0 +1,23 @@
+  SELECT 'Post'::character varying AS model_type, id AS model_id, id AS post_id, uploader_id AS creator_id, created_at AS event_at
+  FROM posts
+UNION ALL
+  SELECT 'PostAppeal'::character varying, id, post_id, creator_id, created_at
+  FROM post_appeals
+UNION ALL
+  SELECT 'PostApproval'::character varying, id, post_id, user_id, created_at
+  FROM post_approvals
+UNION ALL
+  SELECT 'PostDisapproval'::character varying, id, post_id, user_id, created_at
+  FROM post_disapprovals
+UNION ALL
+  SELECT 'PostFlag'::character varying, id, post_id, creator_id, created_at
+  FROM post_flags
+UNION ALL
+  SELECT 'PostReplacement'::character varying, id, post_id, creator_id, created_at
+  FROM post_replacements
+UNION ALL (
+  SELECT 'ModAction'::character varying, id, subject_id, creator_id, created_at
+  FROM mod_actions
+  WHERE mod_actions.subject_type = 'Post'
+  ORDER BY created_at DESC
+)