Support configuring the VCN restriction policy

This commit implements the logic to support configuring
VCN restriction policy on the underlying network. This commit
also adds a stub for later CLs to add the configuration interface.

Bug: 239104955
Test: atest FrameworksVcnTests(new tests)
Test: atest CtsVcnTestCases
Change-Id: I1687df029b5bbd8f20e0e4839ba8bd1717051dcf