Remove Priority of Review Criteria in Admin page, should only be selected when rejecting a translation

Currently the Admin page for defining review criteria allows the selection of the criteria's priority.
The Priority of a review criteria should only be selected when rejecting a translation.

1. Update Database model to allow priority selection when rejecting a translation.
2. Remove priority selection from Admin page review criteria creation.

Open

3. Implement and use a priority selection dropdown in the rejection modal for selecting a priority. (GWT and Alpha Editors)

Open