restructure some values, add imagepullsecrets

• restructure top level values.yaml, remove the concept of "global", scope flux values better
• add imagePullSecrets creation to bigbang chart and add mappings to individual package charts
• add valuesKey for overriding individual. package values with a single configmap (gatekeeper.yaml for instance)
• ensure all bigbang resources are appropriately scoped to a user defined namespace (recommend users deploy the bigbang chart into the bigbang namespace)
• various improvements to pipeline job