Date input component issues

[danielelder]

The govDate component contains the following issues:

• Hard coded hint id, this would restrict the components usage to only one date input per page.
• Hard coded "error:" prefix does not allow for Welsh language translation.
• Error prefix hard coded, see issue The error message component contains hard coded text #18

Observation - The error module looks setup to allow for a list of error messages, normally we would only show 1 error regarding date validation at a time.