Code extracted from:

    https://gitlab.kitware.com/third-party/proj.git

at commit 41bdf05361007f8c5186f3df9944d86bb273ed13 (for/vtk).

The Documentation/dev/git/README.md document is the main dispatch
point for documentation of VTK Git infrastructure.  We should
link to it from the contribution guidelines document.

The actual documentation for contributing to VTK is buried inside
the fourth link when browsing the VTK project. This adds a stripped down
version of how to contribute to the main CONTRIBUTING, and which links directly
to the subsections of develop.md that document each step of the process.

Link to "Documentation/dev/git/README.md".

Change-Id: I45df8e4d2f7931ed3cb0b044f9b15af67e2ca8dc