config.c includes now only the generic helper functions that are needed
both for hostapd and the AP mode operations in wpa_supplicant.
hostapd/config_file.c is only needed for hostapd.
In addition, start ordering header file includes to be in more
consistent order: system header files, src/utils, src/*, same
directory as the *.c file.
Instead of getting this via hostapd.h, include it as the first
non-system header file in all source code files in the same way as
used in all other files.
This makes it clearer which files are including header from src/common.
Some of these cases should probably be cleaned up in the future not to
do that.
In addition, src/common/nl80211_copy.h and wireless_copy.h were moved
into src/drivers since they are only used by driver wrappers and do not
need to live in src/common.
