Standardized admin/consumer configuration file loading/validation.

Basically makes the admin.conf and consumer.conf work like the server.conf.  The consumer.config.py already existed and was being used by the agent.  In this PR, I just expanded it to provide default values and updated the schema for missing values.  Created the admin/config.py following the same pattern.  Last updated the launcher.py and main() methods for both CLIs to use the standard config loading function.