Studio: Authorship Rights Request UI + Dashboard Clean-up

This working branch adds in some additional UI to a Studio User's Dashboard and include the following changes:

* static representations of all possible dashboard states (including with new authorship rights request UI)
* general UI clean-up for all dashboard states (right hand sidebar, help text, logical welcome greetings depending on state)
* re-architected system-help Sass to handle styling of some of the cleanup UI (introductions, status, confirmation notices)

@cahrens, as I mentioned in person, I could use your help to put the proper logic in place to render the proper UI for each use case/scenario. Would you mind as part of your wiring up, trying to abstract this very static mako template? I'm happy to help, but need to know some of the parameters we can use for if statements within the template logic. **Feel free to use this branch as your working one as well - I'll be hands-off until any revisions from the group are needed.**

@markchang, please take a look through these states and make sure they cover the scenarios we're expecting. Also, I could use your help in producing content for the areas where there is now guided placeholder copy. Mind adding that in via comments here or directly into the branch?

@frrrances, mind taking a spin through my new semantics, markup, and Sass additions to make sure they make sense?

Thanks for your help.