Add docs for IPUs

[SeanNaren]

What does this PR do?

Adds docs for IPUs.

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[codecov]

Codecov Report

Merging #7923 (5a91005) into master (024cf23) will decrease coverage by 0%.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #7923   +/-   ##
======================================
- Coverage      92%     91%   -0%     
======================================
  Files         203     203           
  Lines       13151   13151           
======================================
- Hits        12042   12004   -38     
- Misses       1109    1147   +38     

[awaelchli]

nice docs, clean and simple.

[tchaton]

Looks great !