Closed: Resolve "Mobile: can't apply to stores, window cut off", Refactoring to use StoreXHR

See follow up: !1378 (merged)

Closes #765 (closed)

What does this MR do?

Fix #765 (closed) by refactoring the code to work for "stores" as it does for "basket" in the Map View

How confident are you it won't break things if deployed?

Quite likely that some edge cases do have bugs, should be tested by different users

Links to related issues

!1167 (closed) #765 (closed)

How to test

1. Checkout branch locally
2. On the map, click on Stores and try to interact with them (join, cancel request etc)

(Unit tests not possible, as this is mostly a front end change)

Screenshots (if applicable)

Before: After:

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• joined #foodsharing-beta channel at https://slackin.yunity.org
• added an entry to CHANGELOG.md (description, merge request link, username(s))
• Once your MR has been merged, you are responsible to update the #foodsharing-beta Slack channel about what has been changed here. They will test your work in different browsers, roles or other settings