APIs to enable data stall handling in VCN

This commit expose APIs to set VCN Gateway Options for additional VCN
abilities, and the option to allow VCN to detect suspected data stall
and recover with IKE mobility update.

Bug: 261499808
Test: make update-api && make
API-Coverage-Bug: 262297702
Change-Id: If8097d587e7099e9bb9a43328dad3cac3cfb9703