Fix resource utilization data computation, remove requires_mix_precision check

[irenaby]

Pull Request Description:

• Compute resource utilization based on default quantization nbits, instead of hard-coded 8bit. For BOPS use default nbits as well (instead of float).
• Remove requires_mixed_precision check. If target RU is passed, MP is enabled automatically (for 8 -> 16 bit activation) unless only weights are restricted. The check has an overhead of an additional run of graph preparation, and can be beneficial only if target weights utilization is passed and the model already satisfies it. Current implementation is also faulty (should use default bits instead of max bits). Considering all of the above it was decided to remove the check.
• Add unittest for compute_resource_utilization_data and API tests for resource utilization frameworks facades.

Checklist before requesting a review:

• I set the appropriate labels on the pull request.
• I have added/updated the release note draft (if necessary).
• I have updated the documentation to reflect my changes (if necessary).
• All function and files are well documented.
• All function and classes have type hints.
• There is a licenses in all file.
• The function and variable names are informative.
• I have checked for code duplications.
• I have added new unittest (if necessary).