Fix: update to more recent pnet network interface library and ignore routable IPs

[gbusker]

• Current version fails on openwrt MIPS because if-addrs returns IP address in reverse order.
• if-addrs is deprecated so replaced with pnet::datalink
• Added rule to exclude any networks that are not private (10.* etc) when creating a response

[willstott101]

• I'm not sure I understand what you mean by this, could you elaborate? The order of each address is reversed, or the order of the list of addresses?
• I can't find any suggestion that https://crates.io/crates/if-addrs is deprecated, and I've had a good experience getting patches merged for support of different distros in that project already. I've got nothing against pnet though so if it's really solving a problem that could be fine.
• Is there a precedent for this in other mDNS implementations? I guess it kind of makes sense, but is there much of a downside to letting clients prioritise the addresses they use instead of hiding some?

[gbusker]

• I'm not sure I understand what you mean by this, could you elaborate? The order of each address is reversed, or the order of the list of addresses?

I believe this to be an issue with if-addrs on the MIPS platform.
I'll make some time to investigate this further later.

[ArcticLampyrid]

Added rule to exclude any networks that are not private (10.* etc) when creating a response

I don't think this is needed. However, it's good if we can allow the user to customize IPs

if-addrs is deprecated so replaced with pnet::datalink

if-addrs is not explicitly deprecated but actually inactive.
By the way, ip-addrs will get ip that belongs to down interface, but pnet has the func is_up

[willstott101]

With the merge of #35 I don't think the is_private check is the right solution. Users can filter their IPs in their own way now. If you believe there is a bug in if-addrs on a particular platform please open an issue (or ideally, a pull request) in the upstream repo: https://github.com/messense/if-addrs