common: Fix JSON string encoding for control characters

The implementation we got from json-glib is totally broken here
and escapes using octal sequences which are invalid in JSON.

Closes #582
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
ws: use mkstemp() rather than mktemp()

Closes #588

Signed-off-by: Stef Walter <stefw@redhat.com>
 * Whitespace fix
daemon: Bail if storaged isn't running.

Fixes #586
Closes #587

Signed-off-by: Stef Walter <stefw@redhat.com>
 * Changed to a g_message()
ws: Remove some useless rhost stuff in CockpitWebService
ws: Only share sessions if channel uses normal user/key

If a channel requests a specific user or host key, then force a
new session/agent for that channel.
ws: Test that a session without channel times out

This only happens after all channels have been closed. Refactor
things a bit to make testing easier.
ws: No need for tracking the connection in CockpitWebService

Not used for anything any longer. Removing this also fixes
a leak.
agent: Make the authorize cookie a string

This lets us use the polkit agent cookie directly, and also lets
us have a simple implementation in CockpitWebService

Fixes a crasher in the previous commit.
ws: Handle multiple WebSockets per CockpitWebService

Multiple web sockets can be served from a single CockpitWebService,
which allows tabs to share sessions, as well as coherent implementations
of /logout and resource handlers.
ws: CockpitAuth owns CockpitWebService instances

Each time a real login occurs, we instantiate a new CockpitWebService
and return that same instance when logging in with cookies.

When doing /logout we dispose that web service instance, and force
it to disconnect.

Fixes #495
Closes #565