Parallelize code generation for jinja files and code formatting

We want to have fast iteration speed on code generation. https://github.com/project-chip/connectedhomeip/blob/master/scripts/py_matter_idl/matter/idl/generators/cpp/sdk/sdk_generator.py#L120 currently generates a LOT of files and could benefit from paralelization

Update code logic to do parallel generation and test out if this improves runtime (i.e. if it is worth it - this issue was created on the assumption that it is, however we should verify that).

We also do file formatting and those seem to call one single exec to format many files at once. We should investigate if splitting files per cpu count improves formatting (i.e. is clang-format and kotlin-format single threaded or multi-threaded?)