Goal of this issue is to make the Calendar, one of the most important controls in Piwik user interface, usable with the keyboard only.

User story

As a user, using only keyboard and no mouse, I would like to:

• Toggle (open/close) the calendar

• Change the selected period

• Submit modifications using the Apply button

• Select another day, Select another month, Select another year

  This is part of our efforts to make Piwik usable by keyboard, see other issues: https://github.com/piwik/piwik/issues?utf8=%E2%9C%93&q=label%3A%22c%3A+Accessibility%22+