Improve Documentation on Expected Workflow From Issues

[romeara]

Currently, we don't document (or implement) any standardized process for what someone should do if they wish to work on a bug, outside the technical instructions of making code changes. We should determine a standardized approach and add this to our contributor documentation.

For example, we likely want a potential contributor to comment on an issue to "claim" it to avoid multiple people working on the same issue. We also want to specify use of the "Resolves GH-#" syntax in commits when resolving an issue.

This includes the Collaborator documentation - it should be clearly spelled out the steps a collaborator should take for claimed issues, outside pull requests (including labeling, etc)