Integrate PYNQ into fud stage

[nathanielnrn]

As mentioned here:

I think there's one thing that would be good for quality of life: making this all work in fud. I think so far you've been manually invoking your PYNQ host program to run a given .xclbin; is that right? It shouldn't be too much effort to integrate this back into fud, just by making fud execute your PYNQ driver script as a subprocess. This would make it super easy to rerun stuff when doing item 3 above. As a bonus, this would address #1037 by automatically setting up the environment variables for that host-code execution.

Originally posted by @sampsyo in #1022 (reply in thread)

EDIT: Unfortunately none of
#1037
#872
#856
Were addressed