(for 1.8) add power vs save description for talents

Currently, power vs save mechanism is not explained in game, and players can only tell which power/save the specific talent is using for debuff/knockback/... by experience or diving into the code. This merge request add more details in the descriptions of talents, in the form like (Physical Power vs Mental Save). Some helper functions are also provided in DescHelper.lua.

Besides, some minor bugs have been fixed, most of which are inappropriate power used in complex damage type. Higher draconic T1 is worth noting that it contains 5 damage types, each one uses a slightly difference power. This merge request changes that to use physical power & mindpower, whichever is larger.

Note: This merge request changes many files and brings much work for translation. Besides, I currently have no access to dlcs' repo, and the work for dlcs' talents description might need to be done by someone with the access.