Use task queue to spawn multiple processes of tidy

[bwrsandman]

This PR streamlines build_clang_tidy_warnings to be easily dispatched by a multi-process queue. Each process stores the fixes in a temporary directory. The queue will dispatch a clang-tidy process per file to check. This way more complex files can run at the same time as less complex ones. Added a function to combine fixes after the queue is done running.

The design is copied from llvm's run-clang-tidy.py script and adapted for the current code.

Things I've noticed running this:

• On ubuntu actions, this spawns 4 processes.
• Cancelling a workflow only cancels the running queue processes but will still do the post step.
• The logs get spammed. (#128)
• It's hard to tell which log did what.
• A change with 28 files took 17m 45s with 4 processes while upstream took 33m 11s
• The file ranges cover the whole source but each process is a single file.

Depends on:

• [x] #127

Closes #124

[bwrsandman]

@ZedThree fixes done

[bwrsandman]

@ZedThree ping!