use top-level parameters for use_pip & co instead of exts_default_options for PythonBundle easyconfigs

[Flamefire]

It is easier in the top-level and might cause confusion with easybuilders/easybuild-easyblocks#3428

[Flamefire]

Test report by @Flamefire
SUCCESS
Build succeeded for 18 out of 18 (18 easyconfigs in total)
n1552 - Linux RHEL 8.9 (Ootpa), x86_64, Intel(R) Xeon(R) Platinum 8470 (icelake), Python 3.8.17
See https://gist.github.com/Flamefire/b267a7aab05028cfa5974b7b356c0e6b for a full test report.

[boegel]

@boegelbot please test @ generoso

[boegel]

lgtm

[boegelbot]

@boegel: Request for testing this PR well received on login1

PR test command 'EB_PR=21292 EB_ARGS= EB_CONTAINER= EB_REPO=easybuild-easyconfigs /opt/software/slurm/bin/sbatch --job-name test_PR_21292 --ntasks=4 ~/boegelbot/eb_from_pr_upload_generoso.sh' executed!

• exit code: 0
• output:

Submitted batch job 14241

Test results coming soon (I hope)...

- notification for comment with ID 2342901217 processed

Message to humans: this is just bookkeeping information for me,
it is of no use to you (unless you think I have a bug, which I don't).

[boegelbot]

Test report by @boegelbot
SUCCESS
Build succeeded for 18 out of 18 (18 easyconfigs in total)
cns4 - Linux Rocky Linux 8.9, x86_64, Intel(R) Xeon(R) CPU E5-2667 v3 @ 3.20GHz (haswell), Python 3.6.8
See https://gist.github.com/boegelbot/2486e59e8b59efd73727de1ef894e748 for a full test report.

[boegel]

Going in, thanks @Flamefire!