Add new default Vendor node

[wyldclaw]

Vendor nodes are extremely helpful in knowing what transmog, mount, pet, etc. items are still needed from a vendor. We have quite a few here in Dragonflight and I though it made sense to provide a default Vendor group for these types of nodes.

The coins icon is just a placeholder for now. I don't know how to create the glow either. So maybe someone with some more experience can help me make those updates!

• [ ] Update coins icon (or change to new icon)
• [ ] Confirm all vendors have been migrated to new group
• [ ] Finish core localization for new vendors group

[Dathwada]

How about this icon for vendors?

[wyldclaw]

How about this icon for vendors?

This looks great! Makes more sense too since not all vendors take gold. Usually its other currency.