Add settings page to delete user

[FelixTJDietrich]

Motivation

We need to let users delete their account to be compliment with GDPR.

Description

• Add setting page
• Add setting button to user menu
• Add endpoint to delete user (currently just the keycloak user)
• Fix void response for OpenAPI
• Update default keycloak config data with a correctly setup admin client

Testing Instructions

Create an account and delete it via the settings.

Screenshots (if applicable)

Checklist

General

• PR title is clear and descriptive
• PR description explains the purpose and changes
• Code follows project coding standards
• Self-review of the code has been done
• Changes have been tested locally
• Screenshots have been attached (if applicable)
• Documentation has been updated (if applicable)

Client (if applicable)

• UI changes look good on all screen sizes and browsers
• No console errors or warnings
• User experience and accessibility have been tested
• Added Storybook stories for new components
• Components follow design system guidelines (if applicable)

Server (if applicable)

• Code is performant and follows best practices
• No security vulnerabilities introduced
• Proper error handling has been implemented
• Added tests for new functionality
• Changes have been tested in different environments (if applicable)