agl-shell-activator_git: Add recipe

agl-shell-activator_git: Add recipe

This adds the recipe for agl-activator/agl-shell-activator, a simple
tool that switches (already started) applications. It assumes the first
output, but can be enhanced to support use multi output if needed.

Bug-AGL: SPEC-3817

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Change-Id: I32f8bb246d75591cd7fc4f7d4b4047ee2b8f1b09
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/26348
ci-image-build: Jenkins Job builder account
Tested-by: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>