[FHL] New static UX for Keyboard Manager Editor

[haoliuu]

Summary of the Pull Request

• FHL only. Not to merge to the main branch.
• Port the https://github.com/[niels9001/KBMUX](https://github.com/niels9001/KBMUX) from UWP into the new WinUI3 project.
• Update formatting and loading code.
• This is a static UX with mocked data right now.

PR Checklist

• Closes: #xxx
• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Tests: Added/updated and all pass
• Localization: All end user facing strings can be localized
• Dev docs: Added/updated
• New binaries: Added on the required places
  • JSON for signing for new binaries
  • WXS for installer for new binaries and localization folder
  • YML for CI pipeline for new test projects
  • YML for signed pipeline
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx