Support for displaying only due dates and custom date properties in Calendar base view

[thomatino]

Problem:
Currently, recurring tasks do not display their due dates in the calendar base view when both "show due tasks" and "show "recurring tasks" are toggled on. I would love to be able to see all due dates tasks without showing task recurrence instances, so the calender remains clean and focused. This means showing only due dates regardless of whether a task is scheduled, recurring, or otherwise.

Additionally, I often use other date-related properties in my tasks besides the default due date. Currently, property-based events are only accessible for non-TaskNotes tasks. It would be very useful if the base calendar view could also render custom date properties from TaskNotes, allowing users to choose which property should represent the event date in the calendar. This would give more flexibility in task planning and visualization.

Proposed solution:

• Only display due dates in the calendar view for all tasks with a due property when "show due tasks" EVENT is toggled on.
• Add support for rendering custom date properties as calendar events (via property-based events?), allowing users to select which property should be visualized in the calendar, regardless of whether it is a tasknote or not.

Benefit:

• Full visibility of all deadlines(due dates) in the calendar, including recurring tasks without cluttering the view with task reccurence instance
• More flexibility by supporting custom date properties, making the calendar view more adaptable to different workflows.