Open and edit Power BI reportExtensions.json for live connection reports

As an lead developer sometimes i need to correct files prepared by business users. Mostly this is related to issues with measures created for live connected reports (slow/not optimal/ causing other issues). Depending on user number of local measures can vary, but they (end users) are sometimes really creative and there is a lot of measures to be inspected and to be found in the report as they can be hidden in whole model without any pattern.

The same i can sadly say for inspecting old reports - they contain sometimes a lot of measures, sometimes with complex logic and it is hard to navigate in Power BI.

Ability to edit reportExtensions.json file stored in definition catalogue for powerbi project files (with enhanced metadata enabled)

- Open reportExtensions.json and allow editing and write to file.

- There can be some fields which may break report by edit - maybe do not show them in edit view?

- Optionally open metadata from model to allow preview referenced measures from model.