weston-ini-conf: disable locking and idle timeout

weston-ini-conf: disable locking and idle timeout

Disable screen locking and the idle timeout in our weston.ini
shell.cfg and core.cfg fragments, respectively.  This makes the
default configurations more useful for applications like the
agl-ivi-demo-control-panel image, where there is only one
fullscreen application running.  These changes should only affect
Weston based images using the desktop or potentially kiosk shells,
and will have no effect with agl-compositor.

Bug-AGL: SPEC-4952

Change-Id: I947e6f691f0acd4e9d4e3f8583210ec79edcfdb5
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/29341
Tested-by: Jenkins Job builder account
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
ci-image-build: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account