Split FunctionalTests from Mvc solution.

- Created a solution that had everything the `Mvc.sln` had EXCEPT non-functional tests.
- Removed functional tests and websites from Mvc.sln.
- Added `Mvc.FunctionalTests.sln`.

#1227 

**Note:** I kept the `src` folder in the `Mvc.FunctionalTests.sln` to maintain the ability to easily debug the tests. The functional test project depends on the samples so I maintained the `samples` folder as well.