fixes pycqa/flake8/merge_requests!137

Positional arguments are not used nor parsed for pre-configuration
loading.  Thus, renaming the method and updating the docstrings
appropriately.

Now that the preliminary parser is being used, we can remove needing to
prune out `--version` and copying the original `argv` list.

Now that the preliminary parser is being used, we can remove needing to
prune out `-h` and `--help` from the copied `args` list.

Positional arguments aren't necessary for determining where to
load configuration anymore and is safe to keep both options and
arguments to be forwarded for later parsing after configuration is
loaded.

Now that preliminary options are registered with the preliminary parser
on the `Application`, leverage that for parsing known options.

This important change removes the `Application.option_manager` from
being responsible for pre-configuration parsing and the workarounds
needed in the `Application.parse_preliminary_options_and_args()` to
account for the fact that `Application.option_manager` was aware of
*all* options, not just the options necessary for pre-configuration
loading.  A following commit will address removing these workarounds.

The preliminary options and arguments returned from
`.parse_preliminary_options_and_args()` are now all threaded through to
the appropriate methods during initialization.

This is the initial step towards removing state from the `Application`
object during argument parsing and handling.  The goal is to remove
`Application.prelim_opts` and `Application.prelim_args`.