feat(core, postgres): Add RunFunctionWaitStrategy and use it in pg

[jankatins]

I found no way to convert the current container.exec() based check function to any of the currently existing WaitStartegies and so I added RunFunctionWaitStrategy which can be used to convert such container.exec() based checks.

Helps with: #874 Closes: #883

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 80.25%. Comparing base (f608df9) to head (202c8f4).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #908      +/-   ##
==========================================
+ Coverage   79.78%   80.25%   +0.46%     
==========================================
  Files          14       14              
  Lines        1182     1200      +18     
  Branches      184      186       +2     
==========================================
+ Hits          943      963      +20     
+ Misses        197      195       -2     
  Partials       42       42              

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