Auto dismiss angular alerts using user settings

We want the Angular alerts to use the settings from settings.py, so that it matches the behavior of legacy horizon toasts.

Settings here:
https://github.com/openstack/horizon/blob/master/openstack_dashboard/settings.py#L58

    'auto_fade_alerts': {
        'delay': 3000,
        'fade_duration': 1500,
        'types': ['alert-success', 'alert-info']
    },

Since framework cannot be dependent on openstack_dashboard, we need to pass it from openstack_dashboard --> framework.

Related: https://blueprints.launchpad.net/horizon/+spec/client-side-configuration-file