Feat/fftext

[YaoJGalteland]

Description

This file implements the FFTExt and Inverse FFTInverseExt algorithms specifically for elements of a degree 4 extension field (fext.E4) over the koalabear base field. Refactored BitReverse for both the small field and the extension field.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

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

How has this been tested?

Same tests as tests in fft_test.go

How has this been benchmarked?

Same benches as benches in fft_test.go

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I did not modify files generated from templates
• golangci-lint does not output errors locally
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules