Add a postAction for running other templates

[wekempf]

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

Currently there's issue #3208 open to address several pain points, among them is the pain of having to maintain the same .editorconfig file in multiple templates with a suggested solution of adding some common template features behind some parameters. This is a very specific solution that doesn't address the wider problem of having similar needs for file reuse.

Describe the solution you'd like.

Your pain with .editorconfig is not unique to it. Internally we have a few different files that are necessary to exist at the root level in every repository. Specifically for this issue, separate from the other features discussed, I think there should be a postAction for running other templates. Policy to always include a global.json file? Add a post action to run the globaljson template. Policy to always include a build script? Add a post action to run a buildscript template. Policy to always include a Directory.Build.props? Add a post action to run a directorybuildprops template. Etc.

There's minor concern for specifying a template that's not installed so you could consider some way of specifying template dependencies, but honestly just producing an error when the template doesn't exist is good enough.

Additional context

No response

[clazarr]

I think this would be very useful feature! I would add to this request that the proposed Run Template Post Action should be supported in Visual Studio. Most of the existing Post Actions here are not supported/are ignored when the template is run from Visual Studio.