Contribution guide/standards for new contributors

[jbkolze]

Need to come up with guidelines for expected extensions (e.g. prettier), branch management / naming, versioning / releases, reviews, etc. in order to maintain some structure as additional users begin contributing to Groundwork.

[willbreitkreutz]

Needs to include language about using the <Link /> component to allow the LinkProvider to work where used.

[willbreitkreutz]

Topics that a contribution guide needs to cover:

• branching - branch from issue so everything is connected, means every change starts with an issue rather than just an "idea"
• labels - document what labels mean what and when they should be applied
• how to submit an issue/topic for discussion
• versioning guide, talk about semver, what major, minor and patch bump tags to and what they mean
• document the release process so Will isn't the bottleneck, look at release permissions, and NPM org permissions.
• formatting that will be enforced - use prettier

Add Contribution Guide in the "getting started" section as its own page, and link from the block on the home page instead of the link to the GH repo (or in addition to?)