Utility to add meta tags

I would like to see a utility (perhaps in the system menu) to add meta tags. Currently it appears that the only meta tag is meta html which is generated by the php. However, I haven't discovered an easy way for other tags such as keywords, description, robots, or SEO specific meta tags (for Google, Bing, etc.) I think this could be as easy as adding a line or two to the php that would append additional meta tags from a text file to the meta html tag that is generated.