Add CONTRIBUTING and CODE_OF_CONDUCT files

[colekettler]

Since this project is intended as a general-purpose tool, it may receive some interest from community contributors. We should consider following GitHub's recommendation to add a CONTRIBUTING.md file to provide guidance for how external contributors can contribute to this project.

GitHub also recommends adding a CODE_OF_CONDUCT.md file to set expectations for respectful, constructive engagement and repository moderation. This practice also in line with recent positive trends in the OSS community as a whole. We should consider if there are commonly used codes of conduct that align well with our values and ability to moderate potential conflicts. The Contributor Covenant may be a good starting place, and has seen widespread adoption.

[colekettler]

I'm leaving operations labels off of this for now because I don't think this is something that requires us to be involved, though I would personally be happy to facilitate this.

[lederer]

@colekettler Couple of questions…

1. The Contributor Covenant looks like the right choice for a code of conduct. It requires an email address for the community to contact for enforcement issues. This should be a company-level email, rather than an individual. I'm thinking something like conduct@ or opensource-conduct@ or something like that. Do we already have such an address?

2. Some OSS projects require contributors to sign CLA's for permission to contribute code. Eg, our own Raster Vision project, which, like React Showtime, has an Apache 2 license, requires a CLA. My intuition is this would be overkill for a project of this modest size, but I don't really know. Thoughts?

[colekettler]

@lederer Apologies on the massive delay here, but I have answers!

1. I talked about this with Hector, and we could set up a collaborative inbox or list to handle this, with a preference for setting up something for general use across the organization. We haven't dedicated time to figuring out how to best determine responsibility for monitoring it though. Until we have more than one project in need of such an address, are you opposed to using your own Azavea email as a contact?
2. Yeah, I think that would be overkill here and I haven't seen any appetite for requiring it here as well. I don't think we need it.

[lederer]

@colekettler No worries at all. Thanks for the follow up. SGTM!