New CLI subcommand to create clang-compatible compilation database (compile_commands.json) (#14370)

* pulled source from dev branch

* missed a file from origin

* formatting

* revised argument names. relaxed matching rules to work for avr too

* add docstrings

* added docs. tightened up regex

* remove unused imports

* cleaning up command file. use existing qmk dir constant

* rename parser library file

* move lib functions into command file. there are only 2 and they aren't large

* currently debugging...

* more robustly find config

* updated docs

* remove unused imports

* reuse make executable from the main make command

* pulled source from dev branch

* missed a file from origin

* formatting

* revised argument names. relaxed matching rules to work for avr too

* add docstrings

* added docs. tightened up regex

* remove unused imports

* cleaning up command file. use existing qmk dir constant

* rename parser library file

* move lib functions into command file. there are only 2 and they aren't large

* currently debugging...

* more robustly find config

* updated docs

* remove unused imports

* reuse make executable from the main make command

* remove MAKEFLAGS from environment for better control over process management

* Update .gitignore

Co-authored-by: Michael Forster <forster@google.com>

* add a usage line to docs

* doc change as suggested

Co-authored-by: Nick Brassel <nick@tzarc.org>

* rename command

* remove debug print statements

* generate-compilation-database: fix arg handling

* generate-comilation-db: improve error handling

* use cli.run() instead of Popen()

Co-authored-by: Xton <cdewan@apple.com>
Co-authored-by: Christon DeWan <cmdpix@mac.com>
Co-authored-by: Michael Forster <forster@google.com>
Co-authored-by: Nick Brassel <nick@tzarc.org>

lib/python/qmk/cli/__init__.py

@@ -44,6 +44,7 @@ subcommands = [
     'qmk.cli.format.python',
     'qmk.cli.format.text',
     'qmk.cli.generate.api',
+    'qmk.cli.generate.compilation_database',
     'qmk.cli.generate.config_h',
     'qmk.cli.generate.dfu_header',
     'qmk.cli.generate.docs',