Sponsor: add

[aclaire-thd]

Proposal to add the ability to add a sponsor to to the site.

Feature Name
Add sponsor (distinct from assign)

Should be able to add a sponsor from the wish curation list (add sponsor link)

This includes creating the API

There are several parts to sponsor management. This issue will just cover add.

Other issues will cover update, assign, reassign, view + view list (used for assignment)

Notes

[aclaire-thd]

@hellonoosh I think we need a design for the frontend where we'll add new sponsors (distinct from assigning).

What do you think of seeing a list of sponsors that you can pick from or add to?