fixes #7898 - ensure that format can respond to json / yaml
fixes #7985 - add support for ws:// in secure headers
Fixes #7830 - interfaces api output is class specific

- per type rabl templates
- fixed api docs for interfaces
fixes #7331 - delete unassigned os default templates
fixes #7982 - Parameterize Operatingsystem.title to avoid non-alphanumeric characters in title (and friendly_id)