Add hash identity token mode

[jamesagnew]

This PR adds an experimental new feature to include the HASH_IDENTITY column as a predicate whenever searches against the SPIDX_TOKEN table are performed (for positive searches - does not cover :not searches, etc)

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Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 83.55%. Comparing base (406db33) to head (061647d). Report is 69 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #6375 +/- ## =========================================== Coverage 83.54% 83.55% - Complexity 27432 27705 +273 =========================================== Files 1707 1724 +17 Lines 106185 107216 +1031 Branches 13397 13482 +85 =========================================== + Hits 88710 89581 +871 - Misses 11750 11850 +100 - Partials 5725 5785 +60 ```

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