Context:
In order to resolve meta-data of a number of assignee-/candidateGroupIds new endpoints needs to be added.

AT:

• a get assignees by ids endpoint is added that returns:
  • name & email for these
• a get candidateGroups by ids endpoint is added that returns:
  • name for these
• the endpoints are documented at https://confluence.camunda.com/display/CO/Assignee & https://confluence.camunda.com/display/CO/Candidate+groups