Fixes #3525: Filter muiltiple ipaddress terms

[kobayashi]

Fixes: #3525

This makes it possible to filter by mpultiple address terms for ipaddress even w/ or w/o subnet.

$ curl -X GET -H "Accept: application/json; indent=4" -H "Authorization: Token 0123456789abcdef0123456789abcdef01234567" "http://127.0.0.1:8000/api/ipam/ip-addresses/?address=192.168.1.1/24&address=192.168.1.2/24&address=192.168.1.3/24" 
{
    "count": 3,
    "next": null,
    "previous": null, 
    "results": [...]
}

[jeremystretch]

It seems like we're mixing up two different function here:

1. Enable querying for multiple address values; e.g. ?address=192.0.2.1&address=192.0.2.2
2. Enable querying for all addresses within a given prefix, e.g. ?address=192.0.2.0/24

#3525 was scoped specifically to the first function; any other feature would need a new FR first. (However, I think it would make sense to extend this same behavior to the prefix field on PrefixFilter for consistency.)

Regarding the second function, this would need to be provided via a separate filter, as filtering by address implies that you are searching for a specific address. For example, a user might not expect a query for address=192.0.2.1/24 to return anything but that one specific IP.

PrefixFilter is a good reference for this: prefix performs an exact match, whereas within and within_include allowing searching by a given containing prefix. IMO it would make sense to introduce a within filter for the IPAddress model (but again, that would be a separate FR).

[kobayashi]

The PR does not provide prefix filter function. This change extends the current ipaddress filtering method.
If we make a query like address=192.0.2.1/24&address=192.0.2.2, it returnes a specific 2 items.

[jeremystretch]

I just added a whole bunch of tests for filtersets. Can you please expand the test case IPAddressFilter for to test the new multi-value behavior? Per my comment inline, make sure that it checks three cases for mask length: matching, not matching, and not specified.

[kobayashi]

fixes issue of filtering ipaddress with subnet and adds ipaddress filter tests.