This moves the whole getopt setup and analysis out of main() into its
own function in config.c.

The main motivation for this change is to be able to call getopt parsing
and configuration file parsing also from the RPC code path.

In one of the discussion emails about configuration files in CLI and RPC
mode the following architecture was proposed:

apply_config(global_conf)
apply_config(user_conf)
apply_config(pre_conf)
parse_command_line()
apply_rpc_options()
apply_config(post_conf)

And especially for the last step the getopt parsing needs to be out of
main() and callable from the RPC code path.

Signed-off-by: Adrian Reber <areber@redhat.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>