Double to single quotes.
Keep the mix-in priority.
Extended the available logging options on the `cli` tools. Fixes #5609. Fixes saltstack/salt-cloud#616.

There are some changes that need some explanation.
* `--key-logfile` is now deprecated and throws an error letting the user know that --log-file should now be used.
* Each `cli` tool **must** now set the `_default_logging_logfile_` attribute to the default log file path.
* An effort was also made to allow power users to define in the configuration files the common logging settings for each of salt's `cli` tools. For example, for the `salt-call` cli tool, one can set `cli_salt_call_log_level`, `cli_salt_call_log_fmt`, `cli_salt_call_datefmt`, `cli_salt_call_log_file_level`, `cli_salt_call_log_file_fmt` and `cli_salt_call_log_file_datefmt`, leaving the `salt-minion` logging configuration untouched.