standardizing page managers

I wanted to add a fade transition in between pages, but I realized that it gave the impression that performance was slightly slower. So there is no transition added here; I just extracted the common functionality into the page_manager_mixin and brought the landing page controller in line with the other two.
let's revisit this - I need to understand this mechanism and currently i'm feeling uncomfortable seeing it here; because supposedly this abstract page is rendered because of some action that happens OUTSIDE of it

and we are turning around the point of 'waht is the use of router'