Disable deactivated custom field columns before timeline rendering

Conflicts:
	app/assets/javascripts/timelines.js
	app/assets/javascripts/timelines/TimelineLoader.js
	app/assets/javascripts/timelines/model/CustomFields.js
Refactor custom field step
Fix timeline custom field filters

The timeline id is needed by the api/planning_elements_controller to correctly initialize the query
Show filter field set if a boolean custom field filter has been applied