Add VpnManger API surface

This change adds the VpnManager, which will be used by apps to install
profiles for all platform VPN types (currently only IKEv2).

Bug: 143325939
Test: Compiles, FrameworksNetTests passing.
Change-Id: I57f854d0a5b18358f3541c24ca0cd8aed03fd7a1
1 file changed
tree: c1768bbc3f134d4e3c301a1da2a4178f05a3f838
  1. core/
  2. services/
  3. tests/