Enable support to show all dates on Month's Datepicker

I'm trying to enable all data on month calendar but does not work.

I think we can have a option to don't hide some dates.


(The red dates aren't showed by default month datepicker)

#### What is the use-case or motivation for this proposal?

On the advertiser market, the weeks are measured by week, because of this style the users have to navigate between the months to see the full calendar.

Start by locating the month datepicker implementation and its existing tests. Review how dates outside the displayed month are handled, then define the option's expected behavior for showing them and verify the result against the advertiser calendar use case.

Written by the indexing model from the issue text.