Define a contributor ladder guide in the ORAS community repository #51
Description
Along with more new contributors engaged and a few maintainers being inactive, I think we need to define a contributor ladder guide in the ORAS community repository. It should cover both how new Maintainers and org owners are selected, and how existing Maintainers may be removed. There is a template we can reference https://github.com/cncf/project-template/blob/main/CONTRIBUTOR_LADDER.md