It is observed that the api-ref has no doc support for
delete-from-store (/v2/stores/%(store)s/%(image)s) API.
This patch adds the doc support for delete-from-store in api-ref.
bp: delete-from-store
Closes-Bug: #1941038
Change-Id: I5e82ff9f979b80b5b1e06eebea84a1b2fb50c78e