Move webroot out of project.json

[davidfowl]

We should have a default convention based wwwroot in a known location relative to the app base. As an override, it can also be specified as a config option.

[muratg]

@Tratcher Let's get this done before other RC1 items, and remove project.json parsing from Hosting layer.

@BillHiebert FYI. This will have tooling impact that will need to go in RC1. Do you have a tracking bug on your side.

[BillHiebert]

Do now, TFS# Bug 156338

@sayedihashimi

[muratg]

Note: project.json schema will need to change.

[muratg]

@Tratcher Could you file the DNX bug for the publish, test etc change (RC1) as well?