In Cockpit, relative dates are not present in translation file

Problem

• In Tasklist, the relative date fragments used by moment.js are included in the translation file [1]
• This is not the case for Cockpit, which means that relative dates are not translatable
  • If users contribute a Cockpit translation, it is not clear that the relative date fragments used by moment.js needs to be translated as well

Solution
Add dateLocales object to english translation file of Cockpit

[1] https://github.com/camunda/camunda-webapp-translations/blob/master/tasklist/en.json#L400-L489