Transport: Deprecate parsing of port ranges

UnicastZenDiscovery allowed you to specify port ranges for hosts to connect to.
However only the first port was used at all, when specifying something like
`host[9300-9400]`. Updated also the documentation to remove this syntax.

This is the accompanying PR for 1.x, where the removal is done in #7561
not sure I follow here, dont see the link between a debug message and returning a list of 100 addresses