Add new system level APIs for accessing IMS state

1) Adds new system APIs that provide more access to IMS state.
2) Remove dependence on IPackageManager, which is not accessible
in mainline.

Bug: 141457496
Bug: 122098288
Test: atest GtsTelephonyTestCases, atest FrameworksTelephonyTests
Change-Id: I17cbad4642ad3099668a354bb2588f2b55602311