Fix tests on develop

[skullydazed]

Description

Route around make's unique way of doing things so that we can generate header files reliably.

The tests were broken by #11412, specifically this bit. That was added so that compiling in parallel (EG make -j 4) works reliably. However, it turns out that breaks make test:basic.

This started a long quest to find a way to generate include files while still supporting both tests and parallel make. This process has reminded me, once again, that make is a black box filled with suffering and fondant. That brings us to this monstrosity, something I fear will do great harm to my karmic balance.

This PR creates a new command, qmk make, which is designed to sit between Makefile and build_keyboard.mk. It generates include files based on the contents of info.json and then builds the keyboard/keymap in question.

Types of Changes

• Core
• Bugfix
• Enhancement/optimization

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• I have read the CONTRIBUTING document.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[skullydazed]

Thanks to @tzarc's work in #11435 we don't have to unleash this on the world after all.