Initial version of OStree recipe for arm64-generic

Prefix 'apertis/arm64-generic/' is used for branches name.

Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>
Reviewed-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Reviewed-by: Héctor Orón Martínez <hector.oron@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D7277