Documentation: Delete or pare down "contributing to spotlight" wiki page #3569
Description
Description
#3566 moved most if not all of the documentation from https://github.com/projectblacklight/spotlight/wiki/Contributing-to-Spotlight into the README. We should quickly compare the two and if there's nothing crucial that's only in the wiki page, delete it. Otherwise consider whether to add more to the README and then delete, or remove all duplicate info.
If / when we delete the wiki page, make sure there isn't a link to it anymore on the README.