add vpngateway Subcommand

add vpngateway "name_VPN" "name_ADDRESS" SKIP "name_CERTIFICATE"

The following fields are required and can be specified in any order after the vpngateway keyword:

KEY "name_KEY_ALGORITHM"

DATA "name_DATA_ALGORITHM"

MAC "name_MAC_ALGORITHM"

COMPRESSION "name_COMPRESSION_ALGORITHM"

The following fields are optional and can be specified in any order after the "vpngateway" keyword:

TUNNEL "name_ADDRESS"

COMMENT "comment string"