add toolchain nvompic

[SebastianAchilles]

This adds the nvompi toolchain: NVHPC + OpenMPI

[boegel]

@SebastianAchilles I'm not sure what's going on with the tests here...

[boegelbot]

@SebastianAchilles: Tests failed in GitHub Actions, see https://github.com/easybuilders/easybuild-framework/actions/runs/978318613
Output from first failing test suite run:

FAIL: test_docstrings (test.framework.general.GeneralTest)
Make sure tags included in docstrings are correctly formatted.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/runner/1cbbcd4839df37c2ac90961b94f8b7b42f5039f5/lib/python2.7/site-packages/test/framework/general.py", line 124, in test_docstrings
    self.assertFalse(regex.search(txt), "No match for '%s' in %s" % (regex.pattern, path))
AssertionError: <_sre.SRE_Match object at 0x7f29c5f87d50> is not false : No match for '@author' in /tmp/runner/1cbbcd4839df37c2ac90961b94f8b7b42f5039f5/lib/python2.7/site-packages/easybuild/toolchains/nvompic.py

----------------------------------------------------------------------
Ran 782 tests in 979.604s

FAILED (failures=1)
ERROR: Not all tests were successful.

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Request for changes implemented

[akesandgren]

Going in, thanks @SebastianAchilles!