Add support for project-based config file

[ken-duck]

Some features will have need of configuration data, and we cannot get that from the command line since we run as a wrapper. Therefore we want to store configuration in files.

Acceptance Criteria:

• Load configuration from ~/.cheque/config
• Override with configuration from the working directory when cheque is run as "cheque-config.yml"?
  • If the standard linker option that sets the working directory is used, then look for the configuration there
• Config file should be in yml format