feat: ✨ [NEW FEATURE]Create relation between Item and Event, Item and Place, Place and Event

[create-issue-branch[bot]]

Original issue description

**Description of the desired solution** - Instead of manually adding which event a person was in, a relation must be created between the person and the event. Avoids having an item in multiple events. - An item can have a localization, so a relation between place and item is necessary - A event can have a localization, so a relation between place and event is necessary

closes #496