Replace working group edit form

Part of #1409 (closed), #45 (closed) and #9 (closed)

What does this MR do?

Replaces the edit form for working groups with a new vue component. The form uses a new REST endpoint for saving the data and the existing API for picture upload. This removes obsolete picture upload code from XhrMethods. This also removes two obsolete packages that we have been using for image handling.

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

quite sure, unless there are some old image paths that I don't know of

How to test

1. Stay on master, login as bot or orga
2. Go to the edit form of a group that you manage and upload a picture
3. Checkout this branch
4. Go to the edit form of a second group that you manage and edit it, including a new picture
5. Go to the group list page and check that both group pictures are visible

Screenshots (if applicable)

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• set a "for:" label to indicate who will be affected by this change
• added to the next milestone (see https://gitlab.com/foodsharing-dev/foodsharing/-/milestones, unless it has a "for:Dev" label)
• added an entry to CHANGELOG.md
• added a short text that can be used in the release notes
• Once your MR has been merged, you are responsible to create a testing issue in the Beta Testing forum: https://foodsharing.de/?page=bezirk&bid=734&sub=forum. Please change the MRs label to "state:Beta testing".
  • Consider writing a detailed description in German.
  • Describe in a few sentences, what should be tested from a user perspective.
  • Also mention different settings (e.g. different browsers, roles, ...) how this change can be tested.
  • Be aware, that also non technical people should understand.

Release notes text in German