In order to enrich userTask assignee/candidateGroup reports and filter values with metadata like First and LastName of the assignee we need to retrieve the metadata of all known assignees and candidateGroups.
- a dedicated assignee/candidateGroup metadate cache is built up by iterating all distinct known assignee and candidate group ids
- at Optimize startup
- as well as in the same intervals as the `UserIdentityCacheService`
- the sync behavior is the same as for the `UserIdentityCacheService`
Out of scope:
a dedicated configuration will be added with