continuous_integration: add initial manifest

This manifest will be used by our CI infrastructure. It's mainly used for pipelines where we need to deploy/update binaries.

For example, this can be used with the build/build_all.sh and build/release_android.sh scripts to publish bootloaders.

Note that we added a separate manifest because it's faster to repo init/sync only the projects that are needed instead of a whole AOSP tree.

All projects are in https:// format because they are used as "read-only".

Signed-off-by: Mattijs Korpershoek mkorpershoek@baylibre.com