Add flag to create metadata structure if absent

This patch adds --create flag to artifact
metadata update command to force creation of artifact
metadata structure if not present. Moreover
the obsote "precreateKeyReleaseMetadataFile" function is
removed

Change-Id: I663ed60eeb4f9fdf6e0b1500fdafabe980cdeebb
Related-PROD: PROD-34227
1 file changed