[PyCDE][Handshake] Add bindings for Handshake functions

[teqdruid]

Exposes the Handshake dialect's FuncOp in the same style as an HWModuleOp:

class TestFunc(Func):
  a = Input(Bits(8))
  x = Output(Bits(8))

  @generator
  def build(ports):
    ports.x = ports.a & Bits(8)(0xF)

And instantiates them via ESI channels:

class Top(Module):
  clk = Clock()
  rst = Input(Bits(1))

  a = Input(Channel(Bits(8)))
  x = Output(Channel(Bits(8)))

  @generator
  def build(ports):
    test = TestFunc(clk=ports.clk, rst=ports.rst, a=ports.a)
    ports.x = test.x

[teqdruid]

@mikeurbach You might be interested in this.

[mikeurbach]

Very cool!

[mortbopet]

LGTM modulo "locking things down" and only allowing comb and handshake operations inside the Func (... for now).