Convnext achitecture

[Lorenzobattistela]

Implementing ConvNeXt architecture referred in this paper and #353 .

Possible reviewer: @owenvallis

P.S - i'm still getting some problems when formatting with black for me a bunch of other files non-related to my changes are changed, so i did not commit them.

[Lorenzobattistela]

Weird Pytest output, locally everything just works (except for one test that i did not mess up either):

[owenvallis]

Thanks @Lorenzobattistela! Please update the PR so that it's based off the Development branch and is a merge back into Development. I'll try and take a look into the failing test. That seems like there is a mismatch between the layer config we expect in the test and the one we're seeing in your test. This can happen sometimes when TF updates the base class' save config (we likely only want to check the new fields anyways). Can you share what version of TF you're using when the error pops up? Thanks.

[Lorenzobattistela]

Done @owenvallis . Created a new PR based on the dev branch:
#356

#356