feature: month-picker support

[igorlino]

Hi,

Thanks for the effort so far 👍

I have the need to pick months with no particular date in mind. So a month picker.

I used a workaround for this to work: hide the actions, start the picker in year mode, when clicking a month, close the navigation with the selection.

unfortunately, but there is always the posibility to click on the year which navigates to the date view, which is not wanted. I also had to use encapsulation: ViewEncapsulation.None which is not a good idea, due to CSS pollution.

Therefore, we need some few changes to make it work without workarounds.

I will try to create a pull request for adding this feature.

Cheers, Igor