Support for recent pip versions

As noted in #40, the supported pip versions before this release were quite outdated. A major blocker was the dependency resolver that pip==21 introduced. It changed a lot of the internals that we relied on. Thus, we needed to completely overhaul the project.

And we did in #60 🎉 As a result, we now support every pip version starting from 22 with a few exceptions. Of course, given that we need to rely on pip internals without any BC guarantees, there will be some breakages in future version. But we are confident, that the changes that needed to happen in light-the-torch should be small.

In the process of rewriting, we also added support for other PyTorch distributions to be installed through light-the-torch. Before it could only handle

• torch
• torchvision
• torchtext
• torchaudio

but now in addition we support:

• torch
• torch_model_archiver
• torch_tb_profiler
• torcharrow
• torchcsprng
• torchdata
• torchdistx
• torchserve

Unfortunately, overhauling the project also brings some BC breaking changes. Namely, ltt extract and ltt find and their API counterparts light_the_torch.extract_dists and light_the_torch.find_links were removed. This processing in stages, i.e. extracting the PyTorch distributions from the installation command, finding the correct link for them and only then installing them in a subsequent command is no longer possible with the new pip dependency resolver.

Shout out to our contributors: @pmeier @tonyfast @jamesobutler