Feat: Add applications to startpage

[hblitza]

Description

This reorders elements on the startpage:

• display all applications (public or for the specific user if logged in). use a simple web component for this
• removes web socket card

Related issues or pull requests

Pull request type

• Bugfix
• Feature
• Dependency updates
• Tests
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe)

Do you introduce a breaking change?

• Yes
• No

Checklist

• I understand and agree that the changes in this PR will be licensed under the
  Apache Licence Version 2.0.
• I have followed the guidelines for contributing.
• The proposed change fits to the content of the code of conduct.
• I have added or updated tests and documentation, and the test suite passes (run mvn test locally).
• I have added a screenshot/screencast to illustrate the visual output of my update.

[dnlkoch]

This is awesome so far @hblitza!

[dnlkoch]

realm and clientId should be configurable.

[hblitza]

Thanks for the helpful review @dnlkoch. Configuration will me addressed in follow-up PR.