Accessibility - switch labels for the calendar section

[littlesvensson]

Bug description
The labeling of the buttons at the turn of the month is not meaningful. As a result, the function of the switch can sometimes not be perceived by screen reader users.

Steps to reproduce
Steps to reproduce the behavior:

1. Go to the calendar section.
2. Try to use screen reader (for previous mont switch the text is just "prev", for next month "next" etc.)

Expected behavior
Aria labels should be clear enough to be used by screen reader users.