Add new prefix labels

[m-appel]

Because we are adding prefixes from various data sources, we want to attach additional labels to some of them to make their semantic more specific.

The planned labels are:

• PeeringLAN: IXP peering LAN prefixes
• BGPPrefix: Prefixes based on BGP data
• RPKIPrefix: Prefixes based on RPKI data
• GeolocatedPrefix: Prefixes that have geolocation information
• RIRPrefix: Prefixes that are obtained from organizational resources, like the NRO delegations or the IANA special-purpose registries.

This is a list of crawlers that need changes (and double checks if the new labels are correct):

• bgpkit.pfx2asn > BGPPrefix
• ihr.rov > BGPPrefix + GeolocatedPrefix
• nro.delegated_stats > RIRPrefix
• pch.daily_routing_snapshots_{v4,v6} > BGPPrefix
• peeringdb.ix > PeeringLAN
• ripe.roa > RPKIPrefix

[romain-fontugne]

After more reflection on the topic we may prefer to have more specific labels:

• BGPPrefix
• GeolocatedPrefix
• IANAPrefix
• RIRPrefix
• RPKIPrefix
• PeeringLAN

And probably in the future IRRPrefix