fixes #1814 - converts sp_* attributes into a BMC interface class

this patch also includes the following

• added a new interfaces table, and STI objects to represent a NIC, BMC, Managed
  and a bootable interface.
• refactored DHCP/DNS orchestation code, so they can work on the...

added template_kinds controller to api

This commit adds most of the functionality required for API v1

The overall goal was to extract the existing JSON response
overall controllers, and to move them to a seperate name space.

• documentation was added to all requests (available under /apidoc)...

do not report internal state over api

used media/show partial and added to tests

added dns_id, dhcp_id, tft_ip attributes even though they are nested as children to be consistent with current api

typo on index.json.rabl for environments.

added missing s char

update api documentation

• remove #set_resource_params from Api::BaseController to leave :id param under :id for apipie validations to work
• fix custom apipie validators to return nice errors
• enable apipie validations for bugs to be caught early
• log apipie param errors with info level...

• fix user documentation
• remove password_confirmation from user api
• Add json template for users#create

Subnets API