webadmin navigation moved to admin base template

Instead of each webadmin template redefining the webadmin links do it in
the base template. Javascript uses the url to highlight the current
navigation tab for the webadmin page
Fixed admin tab selection

Admin tab selection was relying on a specific url deployment with a set
number of path components. Now it simply looks at the last component
which is reliable
Merge pull request #2367 from dpwrussell/webadmin_nav

Move webadmin navigation to base template