Enable to add a comment to 1 day in general, not under each listing only

I would like to be able to add a general calendar note above calendar dates that are important, such as 'St Patrick's Day today', 'Ireland soccer match this evening', 'Nicki Minaj concert in town tonight, check that no one brings extra guests back at night'. This would really help us at a quick glance to see what happens on a certain date without adding the comment individually to each listing that day. 

Alternatively, I would also like to use this general open field for making my own management notes, such as 'Wash all pillow protectors today', or 'Serve crisps and drinks for all guests today due to St. Patrick's Day', or 'Reception is being painted today, remind guests to be careful". Any notes that would affect the booking situation and/or be important for staff when looking at the arrival calendar for the day. It makes no sense to add these notes to each listing individually, like we have to do now. 

These are separate from Tasks - these are for all staff to see. 

Many thanks