add host additional info filters

[billcobbler]

This change adds the ability to filter additional host info via the list hosts endpoint; a continuation from here, but now filtering is accomplished via SQL.

Additional object without filter:

curl 'https://localhost:8080/api/v1/kolide/hosts'
...
"additional": {
        "macs": [
          {
            "mac": "00:00:00:00:00:00"
          },
          {
            "mac": "02:42:c0:a8:10:05"
          }
        ],
        "time": [
          {
            "day": "13",
            "hour": "3",
            "year": "2020",
            "month": "10",
            "minutes": "43",
            "seconds": "11",
            "weekday": "Tuesday",
            "datetime": "2020-10-13T03:43:11Z",
            "iso_8601": "2020-10-13T03:43:11Z",
            "timezone": "GMT",
            "timestamp": "Tue Oct 13 03:43:11 2020 UTC",
            "unix_time": "1602560591",
            "local_time": "1602560591",
            "local_timezone": "UTC"
          }
},
...

Additional object with filter:

curl 'https://localhost:8080/api/v1/kolide/hosts?additional_info_filters=macs,notreal'
...
"additional": {
        "macs": [
          {
            "mac": "00:00:00:00:00:00"
          },
          {
            "mac": "02:42:c0:a8:10:05"
          }
        ],
        "notreal": null
},
...

[zwass]

Thank you for adding the SQLi fix!

I think the implementation is ready to merge. Before we do that can you please add a test in https://github.com/fleetdm/fleet/blob/master/server/datastore/datastore_hosts_test.go?

[zwass]

In the future please feel free not to implement anything in inmem. It's been mostly removed from use and I need to finish tearing it out.

[billcobbler]

Added tests, but did you also want me to remove this inmem implementation?

[zwass]

No need for that. I'll be removing all of this soon in any case.

[zwass]

Looks great! Thank you for adding the test. I also tested manually in my local Fleet install and it worked as documented.

[zwass]

No need for that. I'll be removing all of this soon in any case.

[zwass]

This resolves kolide/fleet#2329.