Change initial IccCardProxy Card State to UNKNOWN

The IccCard state is an amalgamation of hardware and software
states. This change updates the behavior to clarify and expand
the usage of the UNKNOWN state as follows:
-The initial state of the IccCard is now UNKNOWN (was NOT_READY)
-When the RADIO state is UNAVAILABLE, an ABSENT card state is now
 reported as UNKNOWN rather than NOT_READY
-If the IccCard is present, but the App is not loaded, the
 SIM_STATE will now be considered NOT_READY rather than UNKNOWN.
 This means that the card is present, but the App is not ready.

Bug: 38124100
Test: IccCardProxyTest
Change-Id: I152f789703d7f975f6392ee242da9efd50948a01