feat: Add ModelSummary Callback

[kaushikb11]

What does this PR do?

There are two parts to #9043

1. Introduce ModelSummary callback
2. Support flag weights_summary as Union[str, bool] = True and mark the string values as deprecated (follow up PR)

Does your PR introduce any breaking changes? If yes, please list them.

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[tchaton]

LGTM !

[SeanNaren]

Nice!

[codecov]

Codecov Report

Merging #9344 (a0760c8) into master (c963bf6) will increase coverage by 0%.
The diff coverage is 98%.

@@          Coverage Diff           @@
##           master   #9344   +/-   ##
======================================
  Coverage      93%     93%           
======================================
  Files         179     180    +1     
  Lines       14927   14963   +36     
======================================
+ Hits        13868   13902   +34     
- Misses       1059    1061    +2     

[ethanwharris]

LGTM, minor comment