Documentation to help windows contributors

[Dubes]

This PR is in follow up to the discussion in issue #2828

This introduces a new section in contributing.md for developers using windows machine to help them contribute to this project without relying on workarounds.

Tests:
Below are the screenshot that shows that the steps followed enable devs to use the scripts in the repo as is:

Running Prettier
This shows that windows bash is able to understand unix based paths and patterns without any changes.

Running .sh scripts in tasks folder
This shows that windows bash is able to run the scripts out of the box.

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[cr101]

It would be much easier if this PR #2280 was merged

[Dubes]

@cr101 if that was the only file which caused issue, I would see both these PRs as an either or.
But I faced problems with prettier, running e2e tests etc., so I would see these two PRs as complimentary to each other.

#2280 --> First step of possibly many to enable cross platform development.
This PR as an immediate enabler for windows dev without putting an undue burden on either the devs or the community. From what I read about the windows subsystem for Linux, this kind of use case was the reason they provided that functionality in the first place.

[ianschmitz]

I started an aggregated issue over at #2855 to help us suggest and track improvements for Windows based contributors. Cheers!

[gaearon]

I just merged #2309. Will merge this too now but let me know if any info is outdated.

[Dubes]

Thanks for merging it! To the best of my knowledge, the info is still valid. I just got a vanilla machine and will test the steps, will correct them if needed.

[gaearon]

Amazing, thanks! Please test on the next branch since it's the one where we do active development now.