DIR issues

• DIR-1: return 304 if resource hasn't changed.
• DIR-10: Some enum roles do not work
• DIR-11: Do not allow to link people to inactive GbifRole
• DIR-12: Duplicated email allowed but can't login
• DIR-13: download of reports are unauthenticated
• DIR-14: Support properties expansion in the API
• DIR-15: Support modification of "membership start"
• DIR-16: New role for Nodes Regional Representative Deputy
• DIR-17: Intermittent problems deleting locked files
• DIR-2: relations to inactive participants and nodes should be handled
• DIR-3: trim queries to include only used informations
• DIR-4: Password management
• DIR-5: editing past relations
• DIR-6: Which information is actually useful and should be shown in overviews
• DIR-7: Aggregated data overview
• DIR-8: summary data for landing page
• DIR-9: cannot access past relations in api