EZP-20172: Cached more resources

- /content/objects/{contentId}
- /content/objects/{contentId}/locations
- /content/objects/{contentId}/versions
- /content/objects/{contentId}/versions/{versionNumber}
- /content/objects/{contentId}/versions/{versionNumber}/relations
- /content/objects/{contentId}/versions/{versionNumber}/relations/{relationId}
- /content/locations/{locationPath}
- /content/locations/{locationPath}/children