fixes #3752 - move data population from migrations into seed script

v2 api for configuration_templates and template_combinations

Added additional counter-tests to config templates

Fixes #592 - Adding tests for provisioning template selection based on Host

Fixes #378 - Adds support for multiple configuration templates

Configuration templates (Kickstart, preseed, syslinux, gpxe etc) can now
be saved in the database directly.

Each template is associated with valid operating systems (unless if its a
snippet which can rendered via all other templates) and a possible...