Add peers listing endpoint

[digizeph]

• migrate default broker API endpoint to https://api.bgpkit.com/v3/broker
  • Full API docs is available at https://api.bgpkit.com/docs
• add get_peers to BgpkitBroker struct
  • fetches the list of peers for a given collector
  • can specify filters the same way as querying MRT files
  • available filter functions include:
    • .peers_asn(ASN)
    • .peers_ip(IP)
    • .collector_id(COLLECTOR_ID)
    • .peers_only_full_feed(TRUE/FALSE)
  • returns Vec<BrokerPeer>

#[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
pub struct BrokerPeer {
    /// The date of the latest available data.
    pub date: NaiveDate,
    /// The IP address of the collector peer.
    pub ip: IpAddr,
    /// The ASN (Autonomous System Number) of the collector peer.
    pub asn: u32,
    /// The name of the collector.
    pub collector: String,
    /// The number of IPv4 prefixes.
    pub num_v4_pfxs: u32,
    /// The number of IPv6 prefixes.
    pub num_v6_pfxs: u32,
    /// The number of connected ASNs.
    pub num_connected_asns: u32,
}