docker: Fix libdbus warning when booting fvp

Previously, the fvp would display "libdbus-1.so.3: cannot open shared
object file: No such file or directory" during boot. This was caused by
libdbus being missing. Once added to the container, the fvp started
using dbus to setup audio and emitted more warnings due to libpulse
being missing, so lets add that too.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>