Update TextMate grammar based on vim-syntax

[pboettch]

I upgraded my grammar-generation script I use to generate the vim-syntax-highlighting-rules to put out a TextMate-grammer.

The script can be found here: https://github.com/pboettch/vim-cmake-syntax/tree/textmate-grammer-generation

This change might address item #4508

This changes visible behavior

The following changes are proposed:

• Improved syntax highlighting grammar
• Fine grained keyword/command
• Builtin-variables vs user-variables
• Properties only in property-commands

Other Notes/Information

This is a proposal for discussion. I learnt TextMate-grammar just recently and I'm relatively new to vsCode. There is a lot of space for improvements. Modules are not at all handled, as an example.

Here is a screenshot of a CMake-Files using the Monokai Dimmed-theme