fix(Core/Spells): several improvements to cooldowns (#7559)

- Reworked spell category cooldowns.
- Implemented category cooldowns for pets.
- Properly shows pet spell cooldowns in player's UI.
- Corrected pet spell cooldowns with infinity duration.
- Do not add/remove infinity spell cooldown on aura apply/remove if casted by item.
- Closes #5263

data/sql/updates/pending_db_characters/rev_1629988683345293500.sql

@@ -0,0 +1,4 @@
+INSERT INTO `version_db_characters` (`sql_rev`) VALUES ('1629988683345293500');
+
+ALTER TABLE `character_spell_cooldown` ADD COLUMN `category` MEDIUMINT UNSIGNED DEFAULT 0 NOT NULL AFTER `spell`;
+ALTER TABLE `pet_spell_cooldown` ADD COLUMN `category` MEDIUMINT UNSIGNED DEFAULT 0 NOT NULL AFTER `spell`;