Add environment variable for profiling EasyBuild

[Micket]

Intended usage:

EB_PROFILE=profile.out  eb SomeSoftware-1.2.3.eb

snakeviz profile.out  # nice tool to view profiling data

[branfosj]

$ EB_VERBOSE=1 EB_PROFILE=tmp.out eb --show-config
>> Considering 'python'...
>> 'python' version: 3.6.8, which matches Python 3 version requirement (>= 3.5)
>> 'python' is able to import 'easybuild.framework', so retaining it
>> Selected Python command: python (/rds/projects/2017/branfosj-rse/easybuild/venv-dev-EL8/bin/python)
>> Writing profile output to: "tmp.out"
>> python -m cProfile -o tmp.out -m easybuild.main --show-config
Usage: cProfile.py [-o output_file_path] [-s sort] scriptfile [arg] ...

cProfile.py: error: no such option: -m

But the same works if I use Python 3.9 or 3.12. All Python versions mentioned here are RedHat 8.10 OS packages.