Makefile: undo last changes & completely fix the docker wrappers! It works now!

Makefile: wip: continue trying to fix Docker run wrapper

Makefile: forward all commands to Docker if not already in Docker

docker_run.sh: default the working dir to the PWD if inside the repo...

Makefile: improve it significantly

cpp/Makefile: wip: continue refactoring

wip: Makefile: continue refactoring

wip: add cpp/Makefile as a build wrapper

docker/docker_run.sh et al: add a working dir option...

docker_run.sh: fix bug, moving ` | less -RFX` to the correct place

bash/argument_parsing__3_advanced__gen_prog_template.sh: significantly improve this demo program...

docker/: significantly improve docker_run.sh, and fix passthrough args issue

docker_run.sh: improve architecture and add main() func

docker/entrypoint.sh: default QUIET to "false" only once

docker/docker_run.sh & entrypoint.sh: significantly improve arg parsing...