feat(test): refactor all PolicyDefinitionStore implementors tests by using a base class

[wolf4ood]

What this PR changes/adds

Add a common base test class for PolicyDefinitionStore which all implementors should extends

Why it does that

To have a common and consistent base specification test suite for all implementors of PolicyDefinitionStore

Further notes

• The impl PolicyDefinitionStore#deleteById of CosmosPolicyDefinitionStore has been changed by returning null instead of throwing an exception if the PolicyDefinition is not found
• The following base tests were ignored in InMemory and Comos impl since they do not support yet querying collections fields.
  • find_queryByDuties
  • find_queryByPermissions
  • find_queryByProhibitions
• The following base tests were ignored in the Posgres impl since it does not support yet sorting.
  • findAll_whenSort
  • findAll_allFilters
• In PolicyDefinitionMapping added id mapping for compatibility with InMemory implementation.

List other areas of code that have changed but are not necessarily linked to the main feature. This could be method signature changes, package declarations, bugs that were encountered and were fixed inline, etc.

Linked Issue(s)

Closes #1941

Checklist

• added appropriate tests?
• performed checkstyle check locally?
• added/updated copyright headers?
• documented public classes/methods?
• added/updated relevant documentation?
• assigned appropriate label? (exclude from changelog with label no-changelog)
• formatted title correctly? (take a look at the CONTRIBUTING and styleguide for details)

[codecov-commenter]

Codecov Report

Merging #1959 (72b40b6) into main (67f3b8a) will increase coverage by 0.00%.
The diff coverage is 75.00%.

@@           Coverage Diff           @@
##             main    #1959   +/-   ##
=======================================
  Coverage   62.79%   62.79%           
=======================================
  Files         782      782           
  Lines       16612    16618    +6     
  Branches     1080     1080           
=======================================
+ Hits        10432    10436    +4     
- Misses       5729     5731    +2     
  Partials      451      451           

Impacted Files	Coverage Δ
...osmos/policy/store/CosmosPolicyStoreExtension.java	0.00% <0.00%> (ø)
...smos/policy/store/CosmosPolicyDefinitionStore.java	91.30% <77.77%> (-6.32%)	⬇️
...store/schema/postgres/PolicyDefinitionMapping.java	100.00% <100.00%> (ø)
.../policy/store/schema/SqlPolicyStoreStatements.java	92.30% <0.00%> (+7.69%)	⬆️

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[paullatzelsperger]

LGTM, once the conflicts are resolved I'll merge it