The welcome page content is now inside template/welcome.html

Additionally extracted ContentGrabber class that deals with
extracting content from page.

Caused by myself through moving that logic into Content controller.

Store the state of expanded/collapsed inside the member objects themselves.

So that the correspond to the visual order of things in UI.

Now the welcome part follows the naming convention of the other parts of the app.
There's a Welcome controller and a welcome.Index view.

Moved scrollstate handling to Tabs controller.

Refactor the scrollstate saving logic to not use the global Docs.contentState.