Beginning of REST API documentation. Added info for /hosts endpoint.

[noahtalerman]

The beginning of REST API documentation for Fleet.
I added information for the /hosts endpoint.
A description is needed in the 'additional_info_filters' row of the parameters markdown table.

[noahtalerman]

@billcobbler seeing that #28 is in the process of being approved, it would be awesome if you could throw a description for the additional_info_filters param in the parameters table in this new documentation.

The parameters table:

Name	Type	In	Description
page	integer	query	Page number of the results to fetch.
per_page	integer	query	Results per page.
order_key	string	query	What to order results by. Can be any column in the hosts table.
additional_info_filters	string	query	TODO

Feel free to respond to this comment with your description as well!

[mikermcneil]

lgtm!

Eventually would be good to document the default behavior if order_key, per_page, and page are not specified but that doesn't need to be part of this PR

[billcobbler]

👍 for this PR!

additional_info_filters: a comma delimited list of fields to include in each host's additional information object.

Ideally it'd include a link to the 'additional' host info feature, but I don't see that documented anywhere.

[noahtalerman]

Sweet! Thank you for the quick response.

Ideally it'd include a link to the 'additional' host info feature, but I don't see that documented anywhere.

Noted. The 'additional' host info feature receives an explanation in the below section of the docs, but could receive a more thorough explanation.
https://github.com/fleetdm/fleet/blob/master/docs/cli/file-format.md#fleet-configuration-options

[zwass]

Looks great! Thank you.