Improve date picker in permission tab

The better-dateinput-polyfill doesn't allow us to update styles depending on a button state, because of initialization issue.
use case:

• disabled input has gray label and content
• active input has black label & content

https://github.com/chemerisuk/better-dateinput-polyfill

As an alternative we could use the date picker + calendar we used in timeoffrequest plugin: https://github.com/bendavis78/paper-date-picker