Changes to admin dashboard

Decoupled admin dashboard from data: admin dashboard now is
controller.admin_main_view and is called with url “/admin_main_view”.
The volunteers controller is controller.view_volunteers called with url
(‘/view_volunteers’) by an ajax request.

main.ejs makes two ajax requests and populates “#applications” and
“#volunteers” divs. Tried to make a sample ajax request for volunteers,
but there is some syntax error on main.ejs that needs to be fixed.