[Lua] Add getTotalSkill function to xi.crafting

[Flibe-XI]

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• I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
• I have read and understood the Contributing Guide and the Code of Conduct.
• I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

Add function to crafting_utils to get the total crafting skill + modifiers (gear, support). This will be useful for fishing quests.

Steps to test these changes

local skill = xi.crafting.getTotalSkill(player, xi.skill.GOLDSMITHING)
print(skill)
-- skill should be the players real crafting skill
!additem goldsmiths_apron
-- now it should be real skill + 1