Add PersistentDialog component

[evilkermit]

Summary of Changes

Adding a PersistentDialog component to use in place of VDialog(persistent=True). This will allow us to better control the closing conditions for the dialog.

Checklist

• The PR has a clear and concise title
• Code is self-documented and follows style guidelines.
• Automated tests are written and pass successfully.
• Regression tests (e.g. manually triggered system tests, manual GUI/tool tests, ...) are performed to make sure the PR does not break anything (when applicable)
• Readme file is present and up-to-date.

Documentation Updates

Additional Notes