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>
common: Allow telling pipe not to touch stderr

This should be used in test-server, so that people debugging can
see cockpit-bridge output on the real terminal stderr.
bridge: Ignore possibly fatal warnings when installing polkit agent

This is a workaround for a polkit bug, which emits a pretty strong
g_warning() when it can't install a polkit agent. We ignore this
warning, but also ignore the possibly fatal debugging abort()
here.
common: Include new lines in stderr output when forwarding

When forwarding stderr output to the logs, include new lines so
that the when the messages are also relayed to stderr they look
correct.
ws: test-server now runs cockpit-bridge with fatal warnings/criticals

This allows us to debug problems, run under valgrind, etc.
common: Simpler removing of signal handlers in CockpitPipeTransport
ws: Use 'cat' as a mock bridge in certain tests

This is simpler, faster, and makes a lot less journal and valgrind
noise.