Allow insecure password login for demo

The PZH web server now allows arbitrary login through
usernames and passwords.  This is to support the FIA
demos where access to OpenID is unreliable.

package.json now adds 'passport-local' as a required npm module
app.js loads the passport-local module
The CSS and view have been changed to offer this facility

Note that enrolment and certificate exchange probably doesn't work.

Andrea/Christos: Please let me know if this solves the problem.  Obviously this should be reverted once the demo is over.

Jira issue: unknown (JIRA down)