Sponsor: assign

[aclaire-thd]

Proposal to add assign sponsor to to the site.

Feature Name
Assign sponsor

Functionality
Assign sponsor to fulfill wish
View list of available sponsors
Also reassign

This includes creating the API

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

Notes
This issue only covers assign sponsor.

There are several parts to sponsor management:
add
update,
assign/reassign/view list,
view detail