[Datepicker] Need affordance for open-on-click for inputs

#### Bug, feature request, or proposal:
feature

#### What is the expected behavior?
When i click on input - i want to see calendar without click on icon and input must be focused

#### What is the current behavior?
To view calndar i need click on icon... and input not focused

#### What are the steps to reproduce?
Use datepicker and click on input (not icon) - calendar not opened... when click on icon - calendar opened, but input not focus

Start by reproducing the datepicker behavior described: click the input rather than the icon and observe whether the calendar opens and the input receives focus. Read the datepicker component entry point and its existing tests, if available, then verify that both interactions produce the expected open and focus behavior.

Written by the indexing model from the issue text.