Backports PR #9690
**Commit 1:**
[tribe] Init docs
* Original sha: 42e59dbbe8
* Authored by Jonathan Budzenski <jon@jbudz.me> on 2016-12-28T17:23:21Z
**Commit 2:**
[docs] Init es client section
* Original sha: 92ee7e12a5
* Authored by Jonathan Budzenski <jon@jbudz.me> on 2016-12-29T17:15:55Z
**Commit 3:**
[docs] Link to client api, move client library docs to core development section
* Original sha: deafe5a435
* Authored by Jonathan Budzenski <jon@jbudz.me> on 2017-01-11T20:27:56Z
**Commit 4:**
[docs] Add tribe server settings
* Original sha: a5c322912e
* Authored by Jonathan Budzenski <jon@jbudz.me> on 2017-01-11T20:51:35Z
**Commit 5:**
[tribe] Link to elasticsearch tribe docs
* Original sha: d94ff6f934
* Authored by Jonathan Budzenski <jon@jbudz.me> on 2017-01-11T20:56:40Z
**Commit 6:**
[tribe] Document which nodes server configuration points towards
* Original sha: ecfff93ae6
* Authored by Jonathan Budzenski <jon@jbudz.me> on 2017-01-11T21:14:47Z
**Commit 7:**
[docs] Add index link to elasticsearch clients section
* Original sha: a0e92c3a22
* Authored by Jonathan Budzenski <jon@jbudz.me> on 2017-01-11T22:22:14Z
This overhaul of the docs structure puts Kibana's documentation more
inline with the structure that is used in Elasticsearch. This will help
us better organize the docs going forward as more docs are added.
This also includes a few necessary content changes for 5.0.
