feat: add possibility to click WeeklyCalendar to generate an event at particular time

[d-ivashchuk]

I've been exploring WeeklyCalendar as the alternative to react big calendar but I don't seem to be finding one important feature I would need for my use case. When user clicks an empty place of the calendar is it possible to get the date and time of the clicked cell? so I can generate an event from that click.

thanks for the clarification 😄 and thanks a ton for maintaining the library