Improve test coverage for oae-content

api:

- [x] Execute getContent with a validator error
- [x] Execute canManage with a validator error
- [x] Execute hasAccess with an invalid content id
- [x] Access/share a private piece of content as tenant admin
- [x] Execute getContentMembers with a validation error
- [x] Execute updateFileBody with a validation error
- [x] Reply to a comment with an invalid replyto comment id
- [x] getComments needs a validator
- [x] Execute getLibraryItems with a validation error
- [x] Fetch a group library as an anonymous user (check if we get public items only)
- [x] Request library of a non-user and non-group id
- [x] Execute getRevision with validation error

rest:

- [x] Create unrecognized content type
- [ ] Can we test for a 301/302 response?

librarysearch:

- [x] Search without providing a principal id