Variant selection

• Make the name of projects generic to a setting (project_name)
• Add student preferences
• Add choice workflow, used for just selecting a choice and nothing else (no interest lists, no groupings, just the "project selection" elements)
• Add number to preferences which updates when reordered
• Add end date for project preferences
• Automatically show/hide end date for project preferences based on if project_preferences is enabled.
• Add option to enable/disable student preferences