Harmonize hostname, and move to domain + full_domain

[webmat]

• Gets rid of the last instances of host.name
• Moves to the new standard of domain + full_domain everywhere, including
  under url.
• I added a comment on source & destination's .hostname field. A local agent
  is unlikely to be able to populate this reliably (at best its side of the
  connection). It's expected to be added in as an enrichment. It's also a cue
  that it may be omitted in cases where operational monitoring is the goal,
  rather than security.

Closes #84

[webmat]

We're moving from full_domain to fqdn

[webmat]

@ruflin Ok, host.name commit has been extracted out to #144 :-)

[ruflin]

We can't remove the hostname here but should rename it to url.hostname. These entries are pretty standard for url_parsers across various languages.

[webmat]

I agree that the field url.host.name needs to change to something else. But I disagree that it should become url.hostname.

Please read #84 (comment) to understand why I'd rather introduce domain here instead of hostname.

[ruflin]

The url.hostname is what shows up in the url. It could also be an ip address.

[webmat]

For the record, @ruflin won me over, at least for url.hostname: #147.

The deciding argument was that a URL can either have a domain name or an IP there. So using the word domain was not suitable.

[webmat]

Closing this. host.hostname and url.hostname have been dealt with in #144 and #147 respectively. Also latest discussions have made clear that domain & full_domain were not necessarily the best naming for these fields. Let's wait for consensus to emerge in #84.