Add location filter to the global event calendar

[HaraldWalker]

Is your feature request related to a problem? Please describe.
The global even event calendar show all events and therefore is less usable than the ClimateHub event calendars.

Describe the solution you'd like
Just as on the project browse page the user can also filter events on location.

• with auto-complete search a location can be selected
• a selected place is shown and can be removed again
• filter reset resets also a selected location
• Place the location search below the calendar above the topic filter.
• No not show location search on the event calendar page of a location hub (our climate hubs) but include it on a custom hub (prio1).

Additional context

• Right now, the event calendar filter and the filter on the browse pages for projects, organisations, members do not share any state. This is something we could improve but can do that after implementing this feature as the event calendar then shares two filter options with the other pages.
• The backend should already support it as it is reusing the filtering logic from the browse page.