Configuration subsystem integration

[cidrblock]

Integrate configuration subsystems into ansible-navigator:

Major changes:

• changes in the settings file structure, nesting ee params under the execution-environment ket
• actions that use class App now have an entry and exit function to normalize their ui handling and arg restoration
• many changes to adapt to NOT_SET as the value for parameters that have not been set at all
• remove all cli handling from action as the config subsystem takes care of it
• action log now uses class App as it base to take advantage of enter, exit functionality
• cli_args and config are removed as they are replaced by configuration subsystem
• Moved all application initialization code into initialize.py
• Normalize the signature of all prelogger code to return messages, errors, value
• (where messages is a LogMessage, that can specify a log level)
• introduce ability to write a default location log file with level debug if we sys.exit from the beginning
• changes to tests and test fixtures as required