analyze: plot: place the text on the side with most space

Set the width of the svg to always fit the longest string
while taking its starting position into consideration.

Place the text on the right while the starting point is
in the first half of the screen. After that we put it on
the left to save the svg from being wider that it has to.
analyze: rename variables
detect_virtualization() returns NULL; pass empty string to dbus
bus: use internal helper to read org.freedesktop.DBus.Properties::GetAll variables
hostnamectl: port to sd-bus

Kay:
 - rebase to new transport logic
 - replaced iteration macro with property map
bus: make bus_map_all_properties() call idempotent
sd-login: Fix typo

s/sessio,/session,/
rules: load path_id on DRM devices

The path_id-builtin provides useful unique aliases for DRM devices. If we
want to configure DRM render-nodes for compositors, we want to avoid
storing the whole sys-path in configuration files. Hence, allow users to
store the short PATH_ID instead.

Load path_id-builtin unconditionally on DRM devices now to always provide
this alias.