Issue due date affected by time zone

[silverwind]

Setting a issue due date send a full UTC date due_date: "2020-05-25T00:00:00.000Z" to the backend but depending on the user's time zone, the displayed date may not be 2020-05-25. We should probably convert the time to 00:00 in the user's current time zone and then send UTC for that.

[silverwind]

I guess a better fix is to display the date as UTC (instead of local as right now) while continuing to store 00:00 UTC in the database.