added project listing

Hi,

this is now a larger change. This changes the following things:

- rewrote every url to use /project/:id/...
- project configuration must be changed in webui.conf
- dashboard is now empty (this needs to be implemented next)
- the old dashboard view is the project start page (if you click at a project in the left frame)

For Example:
```
{
   name           => 'Rex Web Delopyment Console',
   server            => "http://localhost:5000",
   secret_passphrase    => 'rex-webui',
   projects => [

      {
         name        => "Sample Project",
         rexfile     => "SampleRexfile",
         description => "This is a sample Project. With a few tasks.",
      },

      {
         name        => "Sample Project 2",
         rexfile     => "SampleRexfile2",
         description => "This is an other sample Project.",
      },

   ],
};
```