New Feature: Allow views to specify a specific plugin layout in order to avoid conflicts

I have a Grails 3.1.10 plugin and application in a gradle multi-project with the following setup:
- Controller in the application that just render a view that is available in the plugin.
- The view in the plugin inherits from a layout also available in the plugin
- When I hit the url of the controller the layout is not applied (but the view is found and the data passed from the controller is rendered correctly)
### Expected Behaviour

The expected behaviour is that the layout from the plugin is applied. This works in Grails 2.3.6.
### Actual Behaviour

The layout is not applied although the view is rendered correctly (but without the layout)
### Environment Information
- **Operating System**: Linux Mint
- **Grails Version:** 3.1.10
- **JDK Version:** 1.8.0_101
- **Container Version (If Applicable):** tomcat running `grails run-app`
### Example Application

I've created a sample app that reproduces the problem: https://github.com/ilopmar/grails3-layout-and-view-plugin.

After cloning the repo:

```
cd myapp
grails run-app
```

And then open the browser and go to `http://localhost:8080/foo/index`

You will see the content of the plugin view but without the layout applied.

If now (without stopping the application) move the file `myplugin/grails-app/views/layouts/main.gsp` to myapp/grails-app/views/layouts/main.gsp` and reload the page, the layout is applied.