…d gatekeeper). Refactored docs in order to explain how to use the new feature and how to use matching_labels args

…d gatekeeper). Refactored docs in order to explain how to use the new feature and how to use matching_labels. Rebased args

…ownscaling-jobs-feature

# Conflicts:
#	README.md
#	chart/templates/rbac.yaml
#	kube_downscaler/cmd.py
#	kube_downscaler/scaler.py
#	tests/test_cmd.py
#	tests/test_scaler.py