This change implements the LSP semantic tokens protocol that has been
introduced with LSP 3.16. Both full and fullDelta requests are implemented.

`range` request has not been implemented

For now modifiers are not handled, this is for three reasons
- clangd doesn't support them yet and that is what I am testing against
- For properly handling modifiers we may have to extend KSyntaxHighlighting
- For now I am aiming to make it simple, solid and fast, modifier
handling can be added later

Signed-off-by: Waqar Ahmed <waqar.17a@gmail.com>