Adding common CLI framework

Fixes #18: adds a framework so all Prosper CLI applications have shared arguments/logger/config
Fixes #17: adds custom_args to log-handle builders so special platform information can be included

Using Plumbum's framework, adds a parent wrapper to provide common args/functionality for CLI writing.

• Handles logging and configuration loading
• Reserves common arguments
  • -d/--debug: set self.debug to avoid spamming production services
  • -v/--verbose: enable logging to stdout
  • --config: load custom config
  • --dump-config: dump default config to stdout for setup

Additional Changelog:

• Removes deprecated functions get_logger & get_config
• Updates docs for prosper_cli
• Adds note to docs about prosper_version behavior