Add UI mode for editing JEA role capability files graphically

[daviwil]

This mode should allow you to easily select which commands and parameters should be available in a JEA role capability file. In theory, you could start with the same UI that the user sees and then use UI actions to enable/disable various commands and their parameters. You should also be able to edit an existing role capability file in this manner.

[daviwil]

/cc @gerane

[gerane]

The other thing I thought would be interesting, would be if the user wasn't totally sure what certain tasks required or wanted a less tedious way to add a number of enabled commands\params, they could feed the UI code snippets and it parse those to fill out the role capability.

There was another idea I'm sort of thinking through. Since the PSGallery has role capabilities, there are many ways phosphor could utilize these. This idea would use known good role capabilities on the gallery to pull information from them to help the user find existing role capabilities that meet their needs, or find similar role capabilities and using them as a starter template, or show the user their configuration so they can use it as a reference.