Show name in Top Clients lists rather than IPv6 addresses

[DL6ER]

@DL6ER

We could theoretically use the network table as a secondary source of information to get IPv6 host names. This would immediately affect all data FTL processes and shows and offer host names in the Top Clients, Query Log, etc. lists.

Added and tested. Awaiting code review.

https://github.com/pi-hole/FTL/pull/648