Fix "Network.app" issues

[osrosal]

• Change icon based on "signal level".
• Don't ask for the password if the network is already saved to etc/wpa_supplicanf.conf.
• Check why the wireless interface is being disabled on app startup. (ifconfig down and up)
• Display a check icon on the currently connected network, a lock icon on the ones protected with password and the signal level.
• Upper limit and ASCII check for Wi-Fi passwords (Network block - psk. Seems like non-ASCII characters are accepted)
• Other issues...