enhance Python easyblock to create non-versioned symlink for python-config + check for bin/python and bin/python-config in sanity check

[VRehnberg]

Occasionally there are configure scripts that assume existance of python-config. But existing easybuild installations for Python3 will only create python3-config. This is a remedy to that problem. Previously discussed here:
https://easybuild.slack.com/archives/C34UA1HT7/p1678728109206609?thread_ts=1678722749.081689&cid=C34UA1HT7

[boegel]

Let's also add python-config --help as sanity check command (so people can easily see that their Python installation is missing the symlink)?

Maybe also add both bin/python and bin/python-config in files in sanity_check_paths (via custom_paths in sanity_check_step) while you're at it...

[VRehnberg]

Let's also add python-config --help as sanity check command (so people can easily see that their Python installation is missing the symlink)?

Maybe also add both bin/python and bin/python-config in files in sanity_check_paths (via custom_paths in sanity_check_step) while you're at it...

I added versioned python-config in path sanity check as well to make it consistent with sanity checks for python. Let me know if you think it's unnecessary and I'll remove it.

[boegel]

lgtm

[boegel]

Test report by @boegel

Overview of tested easyconfigs (in order)

• SUCCESS Python-2.7.16-GCCcore-8.3.0.eb
• SUCCESS Python-2.7.18-GCCcore-11.2.0-bare.eb
• SUCCESS Python-3.7.4-GCCcore-8.3.0.eb
• SUCCESS Python-3.9.6-GCCcore-11.2.0.eb
• SUCCESS Python-3.10.8-GCCcore-12.2.0.eb

Build succeeded for 5 out of 5 (5 easyconfigs in total)
node3170.skitty.os - Linux RHEL 8.6, x86_64, Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz (skylake_avx512), Python 3.6.8
See https://gist.github.com/8a3963c2d9d64df3ab0fa83b2b6aa9b2 for a full test report.