Utilities for managing server configuration via EDN files.  These functions expect a config/defaults.edn to exist
on the classpath as a definition for server configuration default values.  When you call `load-config!` it will
deep merge the file you supply with the base defaults to return the 'complete' configuration.  When loading
configurations a relative path is evaluated against CLASSPATH and an absolute path against the real filesystem.

The values in the EDN files can be :env/VAR to pull a string from an env variable, and :env.edn/VAR to do a `read-string`
against the value of an environment variable.