feat(bigtable): modern Data API policy options

[dbolduc]

Part of the work for #8860

I am going to release the modern Data API in pieces. Starting with the policies and their options. (Note that they are not used anywhere).

The root change is in options.h

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Codecov Report

Merging #9320 (88a825f) into main (88a825f) will not change coverage.
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  Files        1470     1470           
  Lines      134686   134686           
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  Hits       127418   127418           
  Misses       7268     7268           

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