Colour the AST view with the same colors as the source code
* Add a couple of trivial test cases for processAstOutput
* Fix the processAstOutput test, ad a test for a file with #include
* Send individual lines for the AST output
* Parse the source lines for AST
* Register as a contributor
* Factor out the LlvmAstParser into a separate file
Co-authored-by: Arseniy Zaostrovnykh <arseniy.zaostrovnykh@sonarsource.com>
