Cpp translation - initial generation of C++ files

[tanaya-mankad]

There are a couple of distinct changes in this branch, the most major of which is the addition of a cpp (headers only so far) translator that exports .h files to a cpp subdirectory of the build folder.

In addition,

1. pylint warnings have started to be fixed in various python files, including files in the doc directory.
2. Some instances of os.path have been replaced with pathlib Path.

I wanted to get this much work merged before fleshing out the following items:

1. Using the new SchemaFile if possible for the cpp translation
2. Add cpp implementation file generation
3. More pylint fixes and the addition of a CI check for them
4. Complete pathlib transition.

[tanaya-mankad]

The latest checkin contains CPP code generation.