Add salt/utils/cli.py

This new file contains CLI parsing functions that used to be in
salt/utils/__init__.py and salt/minion.py.
Make salt/utils/parsers.py use new CLI parsing funcs
Remove parse_kwarg

This function has been moved to salt/utils/cli.py
Refactor minion arg and kwarg parsing

This commit uses the refactored parsing functions in the new
salt/utils/cli.py, and removes the old yamlify_arg() function to that
file.
rename salt/utils/cli.py -> salt/utils/args.py
Move condition_kwarg to salt/utils/args.py

Also fix refs to that function, as well as to
salt.minion.parse_args_and_kwargs().
Rename parse_args_and_kwargs -> load_args_and_kwargs

Also fix refs, added a function to wrap load_args_and_kwargs, and added
a deprecation warning for kwargs not parsed before being passed to the
function.
Fix traceback when os_fn path does not exist for overstate
Rename a couple functions

Also removed some debugging code and added an option to pass arguments
directly to condition_input.
Fix refs to salt.minion.parse_args_and_kwargs
Fix refs to salt.minion.parse_args_and_kwargs
Fix refs to salt.minion.parse_args_and_kwargs
Change CLI arg parsing to use salt.utils.args.parse_input()
Allow for None to be passed on the CLI
No need to re-parse the data in minion.py

The args will have already been parsed before the arguments get here, so
calling salt.utils.args.parse_input here actually breaks the minion.

Also, made a slight tweak to load_args_and_kwargs().
Rename CustomLoader to SaltYamlSafeLoader

More descriptive this way.
Fix refs to CustomLoader
Make yamlify_arg use our custom YAML SafeLoader