Relocated the month name from header to inside the cell of the 1st day of the month

What?

Removed redundant month and year labels from the header in Month view and Week view. Relocated the month name to 1st day of the month. Fixes issues #962 and #934

Why?

Header text showing the month/week/year under the headerbar, above the month / week view, is now redundant with the sidebar.

How?

Removed the labels from the ui and deleted the-now-unnecessary-code. Appended the month name if it is the first day of the month.

Screenshots

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