Fix #17 #20 #23 #24

[henryleberre]

This Pull Request

• Closes MFC website does not link to MFC code! #17
• Closes cmake build from binary issues #20
• Closes ./mfc.sh builds python packages for venv on first launch without letting the user know #23
• Closes Rename pre_process_code, ...? #24

I also took this opportunity to make mfc.sh print what it does and detect when the CMake binary it sometimes has to download becomes incompatible (and downloads CMake again). It also extracts the required CMake version from CMakeLists.txt at runtime.

[henryleberre]

@sbryngelson There currently is no support for running CI pipelines on GitLab for Pull Requests originating from forks on GitHub (see discussion here). This is why the ORNL pipeline is not running.

The issue I fixed in #18 was actually related to the fact that I was using the commit ref's slug (instead of its name) when running git clone -b <ref> <URL> in the pipeline. I had first thought that the Pull Request was made from the (external) MFC-develop repository but I was wrong. It was a subtle issue because it only fails when the ref (commit name, tag, etc..) is contains certain characters (like capital letters and spaces). Here are the details:

CI_COMMIT_REF_SLUG: CI_COMMIT_REF_NAME in lowercase, shortened to 63 bytes, and with everything except 0-9 and a-z replaced with -. No leading / trailing -. Use in URLs, host names and domain names.

(GitLab: Predefined variables reference)