Streamline contributing experience

Related to #5167.

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The largest part of our contribution guidelines explain contributors how to work on torchvision. Due to sheer amount of techniques and tools that can be quite overwhelming for a new contributor.

I’m going to use $TOOL as a placeholder for what I imagine:

• $TOOL install: Installs torch from nightlies and builds torchvision in the current environment
• $TOOL format: Runs autoformatters
• $TOOL lint: Runs linters
• $TOOL test: Runs tests
• $TOOL docs: Builds documentation

There are a couple of tools out there that do this. Of the top of my head we could use pydoit, tox, or simply make. AFAIK, all of them allow parametrization of the top-level commands so we can provide sensible default while not losing flexibility. For example, $TOOL test will run all tests by default, but dispatches additional arguments directly to pytest.

I can do more in depth research about the tools and which would be the best fit for us if we see this proposal as net-benefit in general.

[datumbox]

Abstracting these details away from contributors might lead to less understanding of how pieces fit together. Perhaps improving our contribution guidelines documentation can make things clearer while not requiring users to use a specific tool that hides the details away. Thoughts?

[pmeier]

Maybe, a bash/bat scripts could be sufficient instead of writing machinery with pydoit or others similar.

We would only have to parametrize the tools whereas we would need to implement the scripts ourselves. Plus, I see two more downsides:

1. Instead of having one config, we would effectively need to maintain 2 scripts
2. My bash and bat scripting experience is minimal and practically non-existent, respectively. The tools that I mentioned are declaritive, so they should be a lot easier to pick up.