Support ISP as metadata

[jimaek]

We already have this info as part of https://globalping-geoip.global.ssl.fastly.net/

"as": {
"name": "internetia sp.z o.o.",

So why not use it. I suggest we start collecting this data from all probes and exposing in our API.
And make it part of POST for measurements too to all users to do limit their tests to certain providers.

Example use-case: I want to understand my performance from AWS to my CDN. Or to choose which Hetzner location I should be using. I could then run a latency test from "network: hetzner".

This means it should also be part of #51

[jimaek]

We also need ISP data to be actionable. It's a new type of location, so the client must be able to ping from internetia and hetzner like he would from a city or a country