Add DisableCollectionNullChecks and EntityFrameworkCompatibilityLayer in the mapper configuration

[alirezanet]

Description

Add DisableCollectionNullChecks and EntityFrameworkCompatibilityLayer in the mapper configuration

Fixes #238

Type of change

• New feature (non-breaking change which adds functionality)

Checklist

• I have performed a self-review of my code
• I have added tests that prove my fix is effective or that my feature works
• I have made corresponding changes to the documentation
• I have commented my code, particularly in hard-to-understand areas
• New and existing unit tests pass locally with my changes

[what-the-diff]

PR Summary

• Modified access level of certain methods
  The methods in BaseQueryBuilder.cs and LinqQueryBuilder.cs were originally only available within their respective classes and could not be altered or called outside them. The access level has now been changed from private static to private which allows for more flexibility within the code.

• Improved null check logic
  The changes now ensure that null check logic uses properties from mapper.Configuration instead of GridifyGlobalConfiguration. This enhancement will help for better handling of null values, specifically when dealing with DisableCollectionNullChecks and EntityFrameworkCompatibilityLayer.

• Addition of new property for null checks configuration
  A new property DisableCollectionNullChecks has been added to GridifyMapperConfiguration. This allows users more control in regulating null checks on nested collections.

• Clarified case sensitivity comments
  The comments regarding case sensitivity in different files were updated for better understanding. This clearly mentions that string comparison is, by default, case-sensitive.

• Added a new test case
  A new test case has been added in GridifyExtensionsShould.cs. This test validates that by disabling null checks, automatic null checks in the mapper configuration can be prevented. This helps in ensuring that the new feature works as expected.