Add RESOLVEIPV6 config flag

[DL6ER]

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Add config flag RESOLVEIPV6=yes|no to specify whether FTL should try to resolve IPv6 addresses to host names or not. Several users (like @WaLLy3K ) have seen issues with IPv6 addresses being resolved to extremely cumbersome generic ISP host names.

This template was created based on the work of udemy-dl.

[AzureMarker]

Change the flag name to RESOLVE_IPV6 so it is more readable, like QUERY_DISPLAY.

[AzureMarker]

Waiting for v2.11.1 to be released