new IccRecord APIs to get plmn and registerForSpnUpdate

those are preliminary works required for carrier identification which
requires plmn and spn for resolution.
1. new API to get PLMN from UICC.
2. new API to register SPN change. SPN is read from UICC initially
but could be override by carrier config and API setOperatorBrandOverride
we need a mechnism to notify registrants that SPN is being updated.

Bug: 64131637
Test: Manual
Change-Id: I7f1b59cf520d95aec14dd02487c48a187b6f55a9