docs(app): adding a mobile first breadcrumb solution

* added a simple breadcrumb solution that works with all mobile devices.
  * just a back to next highest level of api documentation
  * could add in some way to show normal breadcrumbs if on desktop, if needed or wanted.
* added in the old version picker to the top of the left sidebar. No styling just yet. Was going to mess with the left sidebar, but wanted to see if you all like it how it is? I think it should be pinned open all the time, unless on mobile which is default for angular-material, from what I have seen.