Vendor onboarding

1. A new vendor signs up (and is approved, if you use Vendor Moderation).
2. They have no plan until you assign one; My Plan says No plan assigned. Contact the marketplace administrator.
3. Assign a plan on the vendor's page in Vendors → Vendors, or the vendor picks one under My Plan → Available Plans → Select Plan.
4. Arrange payment of the plan fee outside CartWhizz.