Merge branch 'develop' into feature/object_defined_types

Merging in so we get the Modulefile and metadata.json changes.
Added a skeleton user object and accompanying ERB template.
Added an object_username parameter.
Added a closing end tag.
Added a display_name parameter to the user object and rendering of it to the ERB template.
Added an email parameter to the user object and rendering of it to the ERB template.
Added a pager parameter to the user object and rendering of it to the ERB template.
Added a vars parameter to the user object and rendering of it to the ERB template.
Added a groups parameter to the user object and rendering of it to the ERB template.
Added an enable_notifications parameter to the user object and rendering of it to the ERB template.
Added a period parameter to the user object and rendering of it to the ERB template.
Added a types parameter to the user object and rendering of it to the ERB template.
Added a states parameter to the user object and rendering of it to the ERB template.
Merge branch 'feature/object_defined_types' into develop

Merging in to get the icinga2::object::user defined type.
Remove the Modulefile, as it's deprecated as of Puppet 3.6.
Bump up the sizes of the section headers.
Merge remote-tracking branch 'github/develop'
Update license

fixes #6912
Update metadata.json

refs #6912
Update README.md, add doc/installation.md

fixes #6913