Bulk ASN

[UmanShahzad]

Right now we don't support looking up ASNs in bulk, but it's a useful feature to have.

In the process, we should actually support mixing together IPs & ASNs in one bulk lookup, by default.

And as a further improvement to the API, we should deprecate the bulk subcommand and allow automatically looking up things in bulk via e.g. ipinfo 1.1.1.1 8.8.8.8 if the number of inputs is more than 1.

Here's a specific checklist of things to consider:

• support multiple inputs for the no-subcommand case by default, i.e. no need for a bulk subcommand anymore, so write a msg calling it deprecated
• use non-bulk and support pretty format if we're still only with 1 input.
• allow bulk ASN lookups as well, and allow this to be mixed with IP lookups.
• if different data types are used, disallow features that won't make sense for mixed outputs, like csv format, field selection, etc.
• support ASN range selection format such as ipinfo AS1-AS5, which gives ipinfo AS1 AS2 AS3 AS4 AS5.