DB/Spell: fix some enchants proc chances and reduced effects for levels > 60

- Deathfrost:  Slow effect should not work on targets 73 or higher.
- Icy Weapon: proc chance reduced, made to a %-per-hit, should only proc on white hits
- Unholy Weapon: proc chance increased to 3 PPM (based on comments data)
- Battlemaster: should only proc on white hits
- Crusader: effect reduced for players above 60

Closes #7789

(cherry picked from commit e0376d56444f3fa895d321e88b98848a9c9074c7)

sql/updates/world/master/2020_04_25_00_world_2017_02_21_03_world.sql

@@ -0,0 +1,10 @@
+UPDATE `spell_enchant_proc_data` SET `Chance`=2, `ProcsPerMinute`=0, `AttributesMask`=0x3 WHERE `EnchantID`=1894; -- Icy Weapon
+UPDATE `spell_enchant_proc_data` SET `AttributesMask`=0x2 WHERE `EnchantID`=1898; -- Lifestealing
+UPDATE `spell_enchant_proc_data` SET `ProcsPerMinute`=3 WHERE `EnchantID`=1899; -- Unholy Weapon
+UPDATE `spell_enchant_proc_data` SET `AttributesMask`=0x2 WHERE `EnchantID`=1900; -- Crusader
+UPDATE `spell_enchant_proc_data` SET `AttributesMask`=0x1 WHERE `EnchantID`=2675; -- Battlemaster
+
+-- Condition for source Spell condition type Level
+DELETE FROM `conditions` WHERE `SourceTypeOrReferenceId`=17 AND `SourceGroup`=0 AND `SourceEntry`=46629 AND `SourceId`=0;
+INSERT INTO `conditions` (`SourceTypeOrReferenceId`, `SourceGroup`, `SourceEntry`, `SourceId`, `ElseGroup`, `ConditionTypeOrReference`, `ConditionTarget`, `ConditionValue1`, `ConditionValue2`, `ConditionValue3`, `NegativeCondition`, `ErrorType`, `ErrorTextId`, `ScriptName`, `Comment`) VALUES
+(17, 0, 46629, 0, 0, 27, 0, 74, 2, 0, 0, 0, 0, '', 'Spell Deathfrost will hit the caster of the spell if player level must be lesser than 74.');