Switches all samples to use eslint 9 with flat configs. I've tried to migrate existing settings as much as possible. However our eslint configs were also inconsistent so I've tried to align these too
* implement drag and drop in sample
* clean code
* fix reveal command
* remove unnecessary method
* fix getParent to return the existing node instead of creating a new key
* Linting, naming, etc.
Co-authored-by: Alex Ross <alros@microsoft.com>