Change paths on the PZH Web Server

The PZH Web Server currently offers users the path:
 * pzh.webinos.org/main/foo%40bar.com/

This is actually pretty pointless, as we maintain a record of who the user is in the session cookie, and this path is just needless complexity. It also makes all the protocols more complicated.

It has now been changed to a simpler scheme:

* pzh.webinos.org/login - the login page
* pzh.webinos.org/home - the main screen
* pzh.webinos.org/signup - the 'new user' signup page
* pzh.webinos.org/certificates/foo%40bar.com - certificates for user foo@bar.com
* pzh.webinos.org/external/request-access-login - login URL for external connection requests

Also included in this PR is a bit of code to hide the 'approve other user' option until it another user has made a request, and then then a better display when they have.  

The path for 'public' has also been moved out of 'lib' for consistency with the general express framework.

Jira issue: WP-955