R1:b293e6ffed0d

Make Datepicker translatable

Summary: This adds the Ablillity to translate the Content of the Date Picker. It is possible to display more than one Letter for the Day Captions.

Test Plan:
- Change the Language in the User Preferences, make sure it translates 'S|M|T|W|T|F|S' and Months or add the following to the translation.override config to get German Translation:

```
{
'S|M|T|W|T|F|S': 'So|Mo|Di|Mi|Do|Fr|Sa',
'January': 'Januar',
'February': 'Februar',
'March': 'März',
'May'…