update model name from code quality guarantee to collaboration development index

[eyehwan]

The reason I would like to update the name is that, we find that this model is more related to collaborative develoment management, instead of code quality per se. So I change the model name, update descriptions, and add the tags.

[ElizabethN]

@eyehwan Hi and thanks for this! Do we need to discuss this at the next Metrics Models WG or is this something that's already been talked about?

[eyehwan]

Hi @ElizabethN I think we can make a quick decision in the next meeting. :)