Add taylor-green matrix-free and matrix-based example

[blaisb]

Description of the problem

• I have been talking about this forever that we need an example with the Taylor Green vortex.

Description of the solution

• Here it is. It's not 100% finish, but the core of it is.

[blaisb]

@AmishgaAlphonius and @lpsaavedra this is ready for re-review