gitlab-ci: Add scrip to encrypt static delta bundles

The script and debos recipe create a file with 10% plus 18M bigger than the original static delta bundle for filesystem and encryption.
It encrypts the device using Luks/dm-crypt, creates an ext2 filesystem and copy original static delta bundle in it.

Up to 8 keys can be added to the encrypted bundle.
ENCRYPT_KEY_0 should be provided in GitLab CI variable to encrypt bundle.
Other keys, ENCRYPT_KEY_1 to ENCRYPT_KEY_7, are optional.
All keys are copied to calling directory to allow debos recipe to access them.

Signed-off-by: Frédéric Danis frederic.danis@collabora.com