Implement user settings page

[FelixSiegfriedRiedel]

As suggested in #70 "Konto Löschen" should be part of the users settings page.

[astanik]

This issue relates to https://github.com/remsfal/remsfal-frontend/blob/main/src/views/AccountSettingsView.vue

Minimal requirements:

• The user's email address is displayed but cannot be changed
• User can set/add/change first name, last name, address, phone number

[PiaSophieBe]

I would like to do this as a KBA issue.

[astanik]

@PiaSophieBe The backend functionality is provided by https://github.com/remsfal/remsfal-backend/pull/138

Happy Coding!