Add Windows Support for DeepSpeed

[SeanNaren]

What does this PR do?

Closes #6651.

To test this, I think I'll have to mock a bunch of things and ensure initialization works on Windows.

Fixes #<issue_number>

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[codecov]

Codecov Report

Merging #8488 (9f91f9f) into master (0ac9e2a) will increase coverage by 0%.
The diff coverage is 100%.

@@          Coverage Diff           @@
##           master   #8488   +/-   ##
======================================
  Coverage      92%     92%           
======================================
  Files         217     217           
  Lines       14328   14342   +14     
======================================
+ Hits        13222   13236   +14     
  Misses       1106    1106           

[kaushikb11]

@SeanNaren How are you testing it on Windows?

[SeanNaren]

@kaushikb11 I've added a weak test to ensure that the function runs correctly when the platform is Windows, however actually testing this will be extremely difficult. I think we'll rely on user testing + deepspeed to ensure correct communication paths!

[tchaton]

LGTM !

[ethanwharris]

LGTM 😃