Add LSF support

[ajtritt]

What does this PR do?

Replaces #4966

Add support for running PyTorch Lightning on systems managed by LSF.

Before submitting

• Was this discussed/approved via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure your PR does only one thing, instead of bundling different changes together? Otherwise, we ask you to create a separate PR for every change.
• Did you make sure to update the documentation with your changes?
• Did you write any new necessary tests?
• Did you verify new and existing tests pass locally with your changes?
• If you made a notable change (that affects users), did you update the CHANGELOG?

PR review

Anyone in the community is free to review the PR once the tests have passed.
Before you start reviewing make sure you have read Review guidelines. In short, see the following bullet-list:

• Is this pull request ready for review? (if not, please submit in draft mode)
• Check that all items from Before submitting are resolved
• Make sure the title is self-explanatory and the description concisely explains the PR
• Add labels and milestones (and optionally projects) to the PR so it can be classified; Bugfixes should be including in bug-fix release milestones (m.f.X) and features should be included in (m.X.b) releases.

Did you have fun?

Always.

[pep8speaks]

Hello @ajtritt! Thanks for updating this PR.

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2021-07-09 11:43:15 UTC

[ajtritt]

This PR probably requires some changes/additions to the docs. If everyone is okay with these changes I will update the documentation.

[awaelchli]

Let's add the LSF environment class here, I'm going to add tests too.
@ajtritt also added docs improvements to the other plugins, but I removed them from this PR.
We can pick them up again from before my commit
d17281c and add them in a separate PR.

[codecov]

Codecov Report

Merging #5102 (7f127c8) into master (1c825a2) will decrease coverage by 4%.
The diff coverage is 92%.

@@           Coverage Diff           @@
##           master   #5102    +/-   ##
=======================================
- Coverage      92%     88%    -4%     
=======================================
  Files         214     215     +1     
  Lines       13900   13988    +88     
=======================================
- Hits        12814   12309   -505     
- Misses       1086    1679   +593     

[awaelchli]

@ajtritt I implemented the tests. Could you check my edits and my previous comment? Would be great to have this in 1.4. I will request review from others.

[tchaton]

LGTM !

[ethanwharris]

LGTM 😃