expand the source paramter possibilities beyond a single IP or subnetwork

the source parameter in the NamedServerFilter only allows an IP like this :

source=192.168.10.1

or a wildcard pointer to a whole subnetwork like this :

source=192.168.10.%

as of 2.1.4

An interesting feature would be to provide a list of either IPs or subnetwork or even hostnames as value for this parameter like this :

source=192.168.10.%,192.168.21.3,mydckercontainer.mariadb.com

it would allow for example docker containers to be easily configured without previous knowledge of the network, or use of hosts file.