AuthCore: login template/logo now configurable (Catalyst cnf)

Default config is:

  'Plugin::RapidApp::AuthCore' => {
    login_template => 'templates/rapidapp/login.tt',
    login_logo_url => undef
  },

The login_logo_url (defaults to nothing) is read by the login template.
The default login template handles placing it in a sane location.