Split guild_skill_tree

[MrKeiKun]

Is your feature request related to a problem? Please describe. Since not all guild skill exist in pre-re vs re, maybe its time to split guild_skill_tree.txt

Additional context As well as converting it to libconfig :D

[dastgirp]

Personal opinion, I don't think there's renewal specific guild skill, The new skills are in my opinion QoL improvements (Guild Storage, etc) and exist in both pre-re and renewal