Add ability to read specified configuration file for supplicant

[Lewis Rosenthal]

Currently, the supplicant is not passed the parameter to find and read its configuration file. Thus setting specific parameters to pass to it during loading is impossible.

It would be helpful to add this to the load line for the supplicant.

[andib]

Now that my wpa_supplicant v2.7 build allows using a .conf file it may be not to hard to extend xwlan for that too. It would need a new checkbox called something like 'Expert mode - using .conf file'. Specifying the file and path to the .conf file is needed too. By the way add capability to set the path to the wpa_supplicant.exe would be good too.

This all is a bunch of work. Personally I do not need any of that. So I'm not sure if this all is worth the effort. I can not test all the options in the .conf file. I do not even know what they are good for. So before even starting work on this it would be interesting if the whole .conf stuff works and is needed by someone. IMHO the casual user will never need this.

Anyway the first step would be testing wpa_supplicant. Can you test if wpa_supplicant v2.7 with .conf file does what you need? From the Readme.OS2 at ​https://bitbucket.org/Andi_B/os-2-wpa_supplicant/src/e482304561dd4280e4603227955d28d2e65c5397/wpa_supplicant/README.OS2?at=master&fileviewer=file-view-default -

- you can also test wpa_supplicant with a .conf file. F.i. set up a profile
	with no security, switch on wireless and start wpa_supplicant manually
	(f.i. wpa_supplicant.exe -i lan1 -cwpa_supplicant.conf)

[andib]

Beta10 includes the experimental option to use a conf file. Set XWLAN_TECHNOLOGIE_PREVIEW environment variable and check option in WPA Supplicant tab.