rewrite: New Video channels and moderation.

data/migration/v12-13/moderation.sql

@@ -0,0 +1,10 @@
+DROP TABLE IF EXISTS video_exempt_roles CASCADE;
+UPDATE guild_config SET studyban_role = NULL WHERE video_studyban = False;
+
+CREATE TABLE video_exempt_roles(
+  guildid BIGINT NOT NULL,
+  roleid BIGINT NOT NULL,
+  _timestamp TIMESTAMPTZ NOT NULL DEFAULT now(),
+  FOREIGN KEY (guildid) REFERENCES guild_config (guildid) ON DELETE CASCADE ON UPDATE CASCADE,
+  PRIMARY KEY (guildid, roleid)
+);