Add 3D blurpooling and code cleanup for 1D and 2D blurpooling

[nihalsid]

The code had 2D and 1D blurpooling modules which had a lot of code duplicated. Unified that code and added a similar 3D blurpooling module.

Motivation and Context

Adds 3D blurpooling, cleans up code.

How Has This Been Tested?

Compared the outputs of blurpool operators in 2D and 1D for various combination of inputs and parameters to assert that the functionality remains unchanged.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[SungGae]

I tried to apply it to my 3D model and the following error occurred during the basic test. Can you tell me how to solve it?