Add our roadmap to our Readthedocs site #1214
Description
We have discussed the need for a public-facing roadmap and have started to utilize GitHub Milestones to connect big new features to individual Issues (see earthaccess project (view) and https://github.com/nsidc/earthaccess/milestones). It would benefit our community to more prominently highlight our roadmap, perhaps pulling automatically from these GitHub tools if possible so that it stays up to date in one place. By transparently documenting our roadmap and vision, newer contributors will have a better understanding of where to plug in, and what work will benefit the project in the longer term. And, it can also empower our community to provide input and help shape our roadmap together.