apply navbar auto-scrolling to all docs guides
Created by: seanmadsen
In the Dev Guide, these two PRs: #39 and #42 made a UX improvement by automatically scrolling the left navigation bar to the active element, when necessary. We should restructure this tweak so it is a shared resource, applied to all guides that live within civicrm-docs. A simple approach could be referencing one js file. A more sophisticated approach would be creating a custom theme that is used by all guides.