Add restrictions on underlying networks with CarrierConfig

This commit updates the VCN code to use CarrierConfig to
store the restriction policy configuration, and notify
policy listners when the CarrierConfig gets updated.

Bug: 239104955
Test: atest FrameworksVcnTests(new tests)
Test: atest CtsVcnTestCases
Test: manually verified by overriding carrier configs
Change-Id: Iaeb1871b7d9f5c3d1b4e5ec24cfbf79eea58256f