Global.Json Management Support

[matthew-j-clark]

Is your feature request related to a problem? Please describe.

I'm working on some templates for VS that need to deploy or modify a global.json file. This works great in the CLI with post actions, but post actions are not supported in VS. I need to be able to either manage an existing global.json or deploy my new global.json in such a way that it loads in VS.

Describe the solution you'd like.

I'm working on some templates for VS that need to deploy or modify a global.json file. This works great in the CLI with post actions, but post actions are not supported in VS. I need to be able to either manage an existing global.json or deploy my new global.json in such a way that it loads in VS.

Additional context

I can provide screenshots privately as this is for an unannounced feature.