Create Contributing.md (BTC-Miami work phase 4)

[EbonyLouis]

There is a contributing file in the project template repo, copy that file please make sure you update the links and then add the tweaks we discussed below.

From our call, update your file to resemble this Contributing file in our dwn-sdk-js repo. You should be able to primarily copy and paste and add some tweaks to tailor it to your repo.

Things to include:

• Highlight labels they should be aware of 'help-wanted', 'good-first-issue', etc
• how to know if it's being worked on WIP or not 'assigned to nobody' filter, navigate them there or add a link like the ex repo
• Process to follow when working on an issue
• Where they should be posting questions, feature request, etc, discord?

@nitro-neal @mistermoe

[EbonyLouis]

Hi @nitro-neal, I know there's a lot of work to be done before BTC Miami. I also really need this done before then as well. How are you guys looking time-wise? Is this something you guys will be able to get done?

[adam4leos]

has been addressed in #58
closing this one
cc @EbonyLouis