[FR] Delete all timeline events or handle duplicates

[lukerosser]

Is your feature request related to a problem? Please describe.
When regularly importing events from a .csv there's no duplication handling so if working with multiple .csv files that are being updated it causes the timeline to double up after more than one import

Describe the solution you'd like
Either duplication handling or the ability to mass delete events (select all or option to delete the whole timeline in the dropdown)