This change adds a new Avahi browser to detect other vdSMs in the network.
If there are no other vdSMs in the network, the vdSM will proceed as usual, connecting to any new host discovered via Avahi (except noauto ones), and add it to the whitelist with "autoconnect" set to "true".
If other vdSMs are present, the vdSM will connect to a vDC host discovered via Avahi only it is present in the whitelist with "autoconnect" set to "true". If it is not present, it will be added to the whitelist with "autoconnect" set to "false".
Connection to vDC hosts discovered via Avahi when the vdSM starts running is postponed until the vdSM Avahi browser has finished its initial lookup (ALL_FOR_NOW), to ensure that any other vdSMs already present in the network are accounted for.