ws: Serve /cockpit resources in test-server

This allows us to test things with absolute paths

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
base: Implement a AMD loader

This is a standard AMD loader for loading modules with dependencies
and asynchronous loading.

https://github.com/amdjs/amdjs-api/wiki/AMD

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
base: Test AMD using the standard amdjs-tests suite

https://github.com/amdjs/amdjs-tests

We use the basic and anon tests.

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
server: Use AMD async loading for the terminal component

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
base: Quieter messages when not loading via https

We return a 'no-cockpit' problem for callers anyway.

Closes #1370
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
Rename the old dbus code out of the way

So we can implement new stuff with the usual 'cockpit.dbus' and
CockpitDBusJson names.
doc: Document and design new dbus-json3 protocol payload

There will be additions later, but this is the meat of the
protocol.
bridge: Implement a new dbus-json3 protocol payload

This protocol is much simpler than the others. There will be some
additions to it in the future, but at it's core it's about relaying
messages and signals.

We don't have innate object manager support in the bridge, the
javascript code will respond to events and update an object model
there.
base: Implement a javascript client for new dbus-json3

This implements a simple javascript client for dbus-json3. It has
no proxy support at this time, but that will be added later.
doc: Add documentation for cockpit.dbus and related

Closes #1356