Feature: service_network_security_groups from secrets

[bmxpapa]

Hi Team

Would be nice to have a flag that would allow loading service_network_security_groups from secrets

This could be done by a new flag eg: **secret_**service_network_security_groups or similar

Our case:
we have a thousand lines of configuration for each QA environment, the only one difference between each QA are service_network_security_groups, would be nice to deal with duplication, then we can use a trick to promote

secret_service_network_security_groups:

• sg_common_name
• sg_${DRONE_DEPLOY_TO}_name