Integrate HP-FFT Designs

[stefanpie]

Integrate designs from the HP-FFT work

https://github.com/UCLA-VAST/HP-FFT-HLS

The HLS designs appear to be nicely organized in the source repo. Should be minimal effort to port over.

[stefanpie]

#75 Looks like the designs were merged by @ChengyueWang! Will independently test before closing the issue.