UI: VM routing + added intro + ALICE VM page

* changed VM routing
* added a general page for selection
* updated ALICE VM page
* (closes #116)
UI: updated various pages + switch button

* new tab feature to various pages with General/CMS/ALICE views
* new “about physics” page (close #153)
* updated “About” pages (closes #101)
* updated “Getting Started” page (closes #28)