Turn crafting into a F8 skill

Add crafting to the skills list instead of fishing.

• Each craft could add 2 instead of one attempt to the skill count to make it less painful.
• The skill will reduce the amount of failed crafts by skill percentage (0% skill = normal failure rate; 100% skill = zero failures)
• The purity of gems crafted will be increased on the lower end only by skill / 10, so if you have 100% skill and the gem purity you could craft goes from 70% to 90%, it will go from 80% to 90%.
• The purity of wares crafted won't be changed.