Resolve "Mark all Bell Notifications and chat notifications as read"

Closes #935 (closed)

What does this MR do?

This MR added two new buttons in the lists in the topbar. One in the message list and one in the bell list. With this buttons you can mark all messages/bells as readed.

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

Really confident.

Links to related issues

#935 (closed)

How to test

Steps a reviewer can take to verify that this MR does what it says it does e.g.

1. Checkout branch locally
2. Login as foodsaver
3. Write a message to Bot
4. Write a message on the store board
5. Add you to a slot of the store
6. Login with another foodsaver
7. Write again a message to Bot
8. Login with Bot
9. You should have now 2 unread messages and 2 bells. Click on the messages button.
10. Click on the new Button "Alle als gelesen markieren" --> All messages should marked as read.
11. Click on the bells button.
12. Click on the new Button "Alle als gelesen markieren" --> All bells should marked as read.

Screenshots (if applicable)

Text Release Notes

Ab sofort könnt ihr mithilfe der neu hinzugefügten Buttons "Alle als gelesen markieren" alle ungelesenen Nachrichten und Benachrichtigungen als gelesen markieren (Natürlich getrennt von einander).

Checklist

• no unrelated changes
• asked someone for a code review
• set a "for:" label to indicate who will be affected by this change
• use "state:" labels to track this MR's state until it was beta tested
• added an entry to CHANGELOG.md
• add 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 Beta Testing Repo:
  • 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.