meta-pipewire: update wireplumber to 0.5.6

meta-pipewire: update wireplumber to 0.5.6

- use the wireplumber recipe from meta-openembedded (albeit copied
  here with the version changed, because 0.5.6 is not available in
  meta-openembedded)
- rewrite configuration files as needed for 0.5.x
- configure wireplumber with the main service masked, using only the
  template service files for a split-instance configuration.
  split-instance facilitates the multi-container setup that is used
  in the instrument cluster images.

Bug-AGL: SPEC-4934
Change-Id: Ica83f869cdc9527a9edce25e63918a2ba97a4766
Signed-off-by: George Kiagiadakis <george.kiagiadakis@collabora.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/30243
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>