Add APIs for configuring VPN automatic keepalive and IP versions

This change adds support for configuring the keepalive and IP version
overrides within IKEv2 VPNs, enabling power and performance optimization
on a per-network/per-carrier basis.

Bug: 259000745
Test: atest Ikev2VpnProfileTest VpnProfileTest
Change-Id: Ia2015d687b0c4b4195470680e6404c9f35679d3c
3 files changed