weston-ini-conf: make remote output configuration dynamic

weston-ini-conf: make remote output configuration dynamic

Rework things to also update the remote output configuration
fragment based on the value of TRANSMITTER_OUTPUT_HOST.  This
helps when using different IP addresses for e.g. the KVM demo
configuration.

Bug-AGL: SPEC-4618

Change-Id: I198ff3e6a30b3968b4749998354a39325c088933
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
(cherry picked from commit 39def8ebd98c98e67304517ab118f9bde4cdf8e7)
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/28415
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>