Handle additional include paths

[firewave]

Currently no additional includes paths are being passed to the analysis. This may lead to false positives or findings not being reported at all.

We should also indicate that a non-system include wasn't found in the editor (albeit optional).

These need to be made available to the plugin and it seems they are not available yet.

[firewave]

To get the project configurations it is necessary to use CLion-specific functionality. I haven't figured out yet how to develop with them. There also were some recent changes outlined in https://blog.jetbrains.com/clion/2020/12/migration-guide-for-plugins-2020-3/

This probably makes the plugin CLion/AppCode-only but to be honest without the proper data for the file Cppcheck will never give you all the actual results.

[firewave]

If we have access to the build path (I know we can access the workspace path) we could leverage a potentially existing compile_commands.json to get the configuration. Maybe this could be done by leveraging the internal macros mentioned in #40.