For better organization and clarity

• Rename events to calendar_events
• Rename event_attendeees to calendar_event_attendees
• Remove all history's instead use related_id in logs
• rename scheduled_tickets to recurring_tickets
• rename recurring to recurring_invoices
• rename logins to credentials
• rename login_tags to credential_tags
• rename modules to resources
• rename user_permissions to user_client_permissions
• rename ticket_watchers to ticket_collaborators