Skill Levels / Tradable Skills

Please add in a feature to make it so we can level/trade up our skills we find in chest.

For example i have found 4 Kusarigame (Chain Sickle) skills in the last week. Being able to trade those to people for materials or being able to level up their base dmg/ skill up modifiers would make it feel like less of a bad drop from the table and also make it feel like meaningful progression. Even if its a marginal increase it wont be a dud drop.