2020-05-24: backport VPN session summary from cmk1.7.x
2020-05-24: added Throughput section
2020-06-02: renamed from ciso_asa_vpnsessions to cisco_vpn_sessions
            changed item AnyConnect to AnyConnect SVC
            removed system max. sessions from AnyConnect SVC, IPSec RA/L2L and Clientless item infotext