XLA Profiler integration

[kaushikb11]

What does this PR do?

Could approach the XLA Profiler in two ways:

1. Programmatic Capture (on-demand profiling session)
2. Manual capture via TensorBoard - Open TensorBoard with the profile endpoint, and click the “CAPTURE PROFILE” button in the upper left. Enter “localhost:9012” (default) as the profile service URL (this is the address of the profiler server you started in the previous step). Enter the number of milliseconds you’d like to profile for and click “CAPTURE”. The page will refresh with insights after the capture is finished.

Would be so much more fun with Programmatic Capture (But with the current XLA API, finding issues with xp.trace). Not really convinced to hack it around. (Second iteration)

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[codecov]

Codecov Report

Merging #8014 (5c07863) into master (2a372e3) will decrease coverage by 5%.
The diff coverage is 41%.

@@           Coverage Diff           @@
##           master   #8014    +/-   ##
=======================================
- Coverage      93%     88%    -5%     
=======================================
  Files         211     212     +1     
  Lines       13440   13491    +51     
=======================================
- Hits        12474   11854   -620     
- Misses        966    1637   +671     

[awaelchli]

if you update with master it should get the fix for the failing docs build

[awaelchli]

codecov won't reach these lines due to the skipped test? not sure, but you may have to exclude it

[tchaton]

LGTM !

[ethanwharris]

Looks good 😃 some issues with the docs

[ethanwharris]

LGTM 😃