Begin DEVELOPMENT.md -> CONTRIBUTING.md

[handrews]

Create a new CONTRIBUTING.md and link it and DEVELOPMENT.md to each other. Move the recent sections over to CONTRIBUTING.md, and outline sections to organize the various topics that have issues tracking them.

[ralfhandl]

Can we have two links here, this one for new participants to sign up, and another one for existing participants that directly leads to the #spec channel?

[ralfhandl]

Suggested change

	Once you the document is ready, open a pull request.
	Once you the document is ready, open a pull request to the `main` branch.

[ralfhandl]

Also have two Slack links here, one for newcomers, one for returners

[mikekistler]

I think we need a section on "Markdown style". We have a set of conventions for how we write the spec documents -- we should capture these here and say that we enforce some of them with markdown lint (if we do). I think it would also be good to document our conventions for RFC and other links.

[handrews]

@mikekistler this is just to start an outline and populate it with material directly copied over - for additional content, we need to do additoinal PRs.

[handrews]

@ralfhandl@mikekistler I've included all the minor stuff. I don't know how to do the slack thing you want, so please handle that and other requested changes or additions as future PRs- this is just to get the skeleton and port over the sections that could be taken more-or-less verbatim.

[mikekistler]

This looks good as the initial restructure. As @handrews says, there is more to do but I'm fine with leaving that work to future PRs.

[ralfhandl]

@mikekistler Please reapprove & merge

[mikekistler]

Renewing my approval.