In HTML5, you may only use names that are defined in the HTML5 spec or registered on WHATWG’s MetaExtensions wiki page. So these are the two places where you can look for appropriate names.
author
is for the "name of one of the page's authors". As a (CMS) developer, you are probably not the author of the page, right?
application-name
should not be used for the name of the CMS used to create the app, but for the name of the (created) app (only to be used if it’s an app, not for any kind of website).
dcterms.rights
doesn’t seem to be appropriate; it’s for (information about) the rights, and not who has the rights. And besides that, it’s for the created site/app/content, not the tools that made it possible.
You could