Add support for Imbued Supports

[Peechey]

Description of the problem being solved:

Full implementation of Imbued Supports, including Importing from Character, Saving and Loading to the XML, and fixing "too many gems in slot" warning. The selection automatically filters for Level 1 Non-Exceptional Support gems. The colour of "Imbued Support:" will follow the application options Positive Values Hex colour.

You are only allowed one imbued support per Slot.

• If a socketGroup is socketed in and has an imbued and you remove the socketed in, the imbued will be removed.
• If there is an imbued support socketed in Helmet in group 1, and group 2 is also socketed in Helmet, you will not be allowed to select an imbued for group 2. If group 2 is socketed in e.g. Boots with an imbued and then changed to Helmet, the imbued on group 2 is removed.

PS: This PR also removes the Variant column in the skillsTab. It happened long enough ago I forgot it was in this branch. If you don't want it in this change, let me know.

After screenshot:

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<Skill label="" enabled="true" slot="Helmet" mainActiveSkill="1" mainActiveSkillCalcs="1" imbuedSupport="Spell Echo" includeInFullDPS="false">
		<Gem enabled="true" quality="0" variantId="FlameSurge" skillId="FlameSurge" level="20" enableGlobal1="true" count="1" enableGlobal2="true" nameSpec="Flame Surge" gemId="Metadata/Items/Gems/SkillGemFlameWhip"/>
		<Gem enabled="true" quality="0" variantId="SupportInvertTheRules" skillId="SupportInvertTheRules" level="3" enableGlobal1="true" count="1" enableGlobal2="true" nameSpec="Invert the Rules" gemId="Metadata/Items/Gems/SupportGemInvertTheRules"/>
		<Gem enabled="true" quality="0" variantId="SupportArcaneSurge" skillId="SupportArcaneSurge" level="20" enableGlobal1="true" count="1" enableGlobal2="true" nameSpec="Arcane Surge" gemId="Metadata/Items/Gems/SupportGemArcaneSurge"/>
		<Gem enabled="true" quality="0" variantId="SupportCullingStrike" skillId="SupportCullingStrike" level="20" enableGlobal1="true" count="1" enableGlobal2="true" nameSpec="Culling Strike" gemId="Metadata/Items/Gems/SupportGemCullingStrike"/>
</Skill>