Deprecate print_error function and replace it with new print_error_and_exit function

[Flamefire]

There is a print_error function in output and this one additionally
exits which is not reflected in the name.
Also the handling of the parameters is confusing, e.g. using log to
determine whether to throw an EasyBuildError.
Deprecate it and replace by print_error_and_exit, translating the
arguments from one to the other.

CI error is due to use of log.error which is disallowed since #1218

Only easybuild.base seems to be exempted with a comment (which seems to be outdated)

# don't check Python modules in easybuild.base namespace (ingested vsc-base)

That is also the source of the weird construct:

elif log is not None:
        raise EasyBuildError(message)

TBH I don't really like having EasyBuildError log an error in all cases as we sometimes catch it and do something else instead. But maybe this just means we should not raise it so often.

I removed the log parameter (again)

[boegel]

End out produced output will look like this:

All long option names can be passed as environment variables. Variable name is
EASYBUILD_<LONGNAME> eg. --some-opt is same as setting EASYBUILD_SOME_OPT in
the environment.
ERROR: Please provide one or multiple easyconfig files, or use software build options to make EasyBuild search for easyconfigs

So the error message "drowns" a bit because it blends in with the short help output.

Let's add one (or two) newlines in between?

[Flamefire]

Note that this was the case before.

We have output.print_error which adds a newline before and after the message. Would be great if we could use that. A bit confusing that print_error are in output but print_msg and print_warning in build_log. I'd move all to one of them but we can't as we either get a cycle or break backwards compat with build_log.print_error (which used to exit)

I'm now calling output.print_error from here to have a uniform appearance of printed errors.