CMake - Base PSI support for PyCharm and IntelliJ

[Noam-Dori]

Feature: basic language support for non CLion IDEs

Background Issue #69 gave clear insight that using existing plugins can't work. Therefore, this plugin must implement CMake on its own. Without it, 46% of the userbase will not be able to use features that utilizes CMake in any way (which, in ROS, very few features don't)

Details

• [x] Create the language file without the PSI tree. This feature should be disabled in CLion.
• [x] Create a PSI tree for CMake files. To do so, use modern .bnf and .flex files that generate code for it.
• [x] Add a highlighter and highlighting menu for the CMake files.
• [x] Add a public function that can let the developer know whether CLion's CMake or the in-house CMake is active
• [x] Add a commenter, and a brace matcher to the in-house CMake lang.

[Noam-Dori]

While everything here was technically resolved, the highlighting and PSI is very basic - it covers all CMake instances, but doesn't do anything smart with it. For this, an advanced annotator is necessary.