show created_on & updated_on in Listing of time entries

Hey Folks,

i like to enhance the default view / table of the time entries so that there are to more columns with the created_on and updated_on values.
Both Values are stored in the corresponding database table. We are using Redmine 3.4.3 and maybe someone can help me to get this done.
Unfortunately both columns are not available from the context menu (available columns).