nested entities should be summarized by walker

Story : Walker should not show VPN secrets, so that information remains
secured

while implementing GatewayIpsecVpnService we found that the
entity.summary does not render summary correctly if entity has nested
entity within it. This particular commit fixes this problem
.
Whitelisting only required vpn service info
hack. merged whitelisted vpn service hash with edge_gateway
masking shared secret info if present
removed end_point since fog never returns it

Fog does not return end_point with remote network. We are not sure if it
return this field for other vpn types. For now removing this.
fixing incorrect mock
printing information in fog format

vclloud-walk edgegateway spits data in fog format. Using fog format for
IpsecVpnService, so that we are consistent.
should include only whitelisted vpn info
should walk vpn service with multiple tunnels