Changes to `ingest-qonnx`

Created by: thesps

@jmitrevs some updates for you.

Firstly, I've pulled master branch to bring this up to date.

Secondly, the main thing I've changed is that Quant nodes don't get converted to BatchNormalization any more.

Now, a Quant node with a Constant node 0th input is replaced with a Constant. It's basically the same logic as what you previously did, but instead of the node going through transformations like Quant to BatchNormalization to Constant, it just goes Quant to Constant. I'm not 100% sure that scale and zeropt are handled properly, but I haven't changed the behaviour of that just yet.

A Quant node with something that is not a Constant node as its 0th input is replaced with an Activation (linear). If one of these Quant nodes has a scale or zeropt, an ApplyAlpha (aka BatchNormalization) is inserted to take care of that. Again, some more verification is needed that we're handling those correctly.

I've also added a test_qonnx.py with a test of the TFC_2w2a model that works locally, but not yet in CI because I think I messed up the environment. I'll fix that...