Handle ascii encoded SSID

Supplicant now passes as an ascii encoded string that allows it to
pass any sequence of bytes for a SSID. see src/utils/common.c in supplicant
for details of the implementation.

We create a SSID structure WifiSsid in framework to store the ssid and handle
the conversion appropriately when required for printing and for an application.

At this point, we still do not handle non-printable octets from an application perspective
for connectivity

Bug: 7110903
Change-Id: I520e5ee23baed4867b8b408bbb3eda5c9e92b6bf