Add RaspberryPi 5 platform template

Add RaspberryPi 5 platform template

This adds templates to build for the RaspberryPi 5 platform.

Note that meta-raspberrypi doesn't yet have U-boot updates for the platform,
will be added later.

Bug-AGL: SPEC-5094

Change-Id: Idede92ca5d9b678ee2f9ea0869e64da04dd719ea
Signed-off-by: Denys Dmytriyenko <denys@konsulko.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/29735
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jenkins Job builder account
ci-image-build: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account