Add Restricted Mode Firewall Chain

Adding new allowlist firewall chain to support restricted networking
mode. See go/restricted-networking-mode.

Bug: b/157505406
Bug: b/170323408
Test: atest NetworkManagementServiceTest
Change-Id: I8e39b3d7b129ad74224d0c1311135b7b48f6514f
1 file changed
tree: 67692ee75310cf174adc81c96f0509c139392b9c
  1. core/
  2. services/
  3. tests/