update PyTorch 1.4 easyconfigs to use custom easyblock (and do less downloading during installations)

[Flamefire]

This uses the script from https://github.com/easybuilders/easybuild-framework/blob/develop/easybuild/scripts/createSubmoduleDeps.sh to update dependency downloads and updates the foss EC to mirror the fosscuda EC.

• Requires explicitely enable/disable CUDA options in PyTorch easyblock + fix download check in sanity check + fix for disabling of *NNPACK on POWER systems easybuild-easyblocks#2164 to build the foss EC

[Flamefire]

Test report by @Flamefire
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in this PR)
taurusml24 - Linux RHEL 7.6, POWER, 8335-GTX, Python 2.7.5
See https://gist.github.com/1202a8e2a5271673c04f1f0146758b94 for a full test report.

[boegel]

Test report by @boegel
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in this PR)
node3404.kirlia.os - Linux centos linux 7.8.2003, x86_64, Intel(R) Xeon(R) Gold 6240 CPU @ 2.60GHz (cascadelake), Python 2.7.5
See https://gist.github.com/b2277390330cca294cf2befec129ad9f for a full test report.

[boegel]

@boegelbot please test @ generoso
EB_ARGS="--include-easyblocks-from-pr 2164"

[boegelbot]

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

PR test command 'EB_PR=11219 EB_ARGS="--include-easyblocks-from-pr 2164" /apps/slurm/default/bin/sbatch --job-name test_PR_11219 ~/boegelbot/eb_from_pr_upload_generoso.sh' executed!

• exit code: 0
• output:

Submitted batch job 5265

Test results coming soon (I hope)...

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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).

[boegel]

lgtm

[boegel]

Test report by @boegel
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in this PR)
node3300.joltik.os - Linux centos linux 7.8.2003, x86_64, Intel(R) Xeon(R) Gold 6242 CPU @ 2.80GHz (cascadelake), Python 3.6.8
See https://gist.github.com/cc56d78ffbfb6803be91586127653947 for a full test report.

[Flamefire]

Test report by @Flamefire
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in this PR)
taurusa7 - Linux centos linux 7.7.1908, x86_64, Intel(R) Xeon(R) CPU E5-2603 v4 @ 1.70GHz, Python 2.7.5
See https://gist.github.com/a5bcdd8bc1e0fa987739754ce58dd435 for a full test report.

[boegelbot]

Test report by @boegelbot
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in this PR)
generoso-x-1 - Linux centos linux 8.2.2004, x86_64, Intel(R) Xeon(R) CPU E5-2667 v3 @ 3.20GHz (haswell), Python 3.6.8
See https://gist.github.com/f0c7f78a6ac001495dfc020d3ee9352b for a full test report.

[boegel]

Going in, thanks @Flamefire!