Implement minimal built-in checks for Ibis backend

[deepyaman]

This implements the built-in check machinery and a single validation (equal_to). In future PRs, I (or somebody else) can:

• Add more built-in checks
• Add more datatypes and make sure they work with the built-in checks

[codecov]

Codecov Report

Attention: Patch coverage is 94.73684% with 1 line in your changes missing coverage. Please review.

Project coverage is 92.91%. Comparing base (ffe6c55) to head (e0f868d).

Files with missing lines	Patch %	Lines
pandera/api/ibis/components.py	83.33%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           ibis-dev    #1885      +/-   ##
============================================
+ Coverage     92.76%   92.91%   +0.14%     
============================================
  Files           133      134       +1     
  Lines          9705     9722      +17     
============================================
+ Hits           9003     9033      +30     
+ Misses          702      689      -13     

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