feat(developer): add `-m` parameter to control message display

Fixes #10150.

This feature adds a command line parameter to kmc to control the
severity of INFO, HINT and WARN level messages. The severity of any of
these messages can be reduced all the way to INFO, or even disabled, or
increased to ERROR. The compiler and the reporter will honour the new
code and fail builds when failure-level codes are encountered.

Inputs are validated against all the available compiler messages in all
modules. This also provides a good pathway for automated future
documentation generation of compiler messages.

In order to process the input parameters cleanly, have refactored some
of kmc's build command logic.

This commit increases code coverage for kmc to roughly 50%.