task: investigate global configuration loading

[GrantBirki]

This issue tracks work to investigate how configuration loading takes place. I am noticing an issue where sometimes I might set log_level: debug in my global config but then it only logs at an info level.

We need to investigate the order of operations that config options take place. It should behave like this:

1. Options from Hooks.build(config: <config>) are applied first
2. Any environment variables that are set and have valid values override the config options or global config file values
3. A log message is displayed at the info level if any overrides are made

We also need to make sure that all the values in GLOBAL_CONFIG_SCHEMA are actually able to be overridden via HOOKS_... env vars. For example, it looks like HOOKS_USE_CATCHALL_ROUTE is missing among others.

If any sort of errors occur during Hooks.build() with either the global or endpoint configs, meaning information/logs and error messages should be displayed.