Add week numbers to month view

[frigsfrogs]

I have seen several threads regarding week numbers in the month view. So it will be possible to see the week number (1-52) to the left of each week in the month view like below:

But it's not described in any of the comments if this is possible or not, and if it is, then how to enable it. So i guess this is not currently supported.

In Denmark we very much use these week numbers for vacations etc., so it's a valuable thing to be able to present to the users.

Here are a couple of threads I have read:

#117
#1059