This change allows some make targets to be ran outside the dev-container for
easier discovery and use:
- `make clean` can be used on the host (as artifacts created from within the
development container are usually stored on the host).
- `make help` was already allowed
- `make dev` and `make shell` are added to the regular Makefile, to make it
easier to create and start the development container.
- When attempting to run `make dev` from within the development container, a
message is printed, and the target is cancelled:
root@docker-cli-dev$ make dev
you are already in the dev container
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
94e08f2e2d