Disallow multicast ranges in interface prefixes

[ipspace]

Based on #1777 (comment) by @jbemmel

However:

• We still cannot use the same type check for regular and loopback prefixes
• We cannot disallow multicast ranges in prefix checks as the prefix we check might be coming from a prefix-list

Either we implement the "interface IP address sanity check" later in the process (turning the check_host_bits into something more generic) or we implement tons of variations of the IPv4/IPv6 address type validation.

I think I'll go with the former even though in theory the type validation should catch more errors (because someone might forget to call the interface_address_sanity_check)