impl/EZP-21681: Implement ContentTypeList without Identifier or RemoteId (DO NOT MERGE)

The goal here is to implement in the REST ressource that can get the whole list of contentType.
The ressource can be call with GET /api/ezp/v2/content/types
We can choose an offset and a limit which are optionnal.
e.g. GET /api/ezp/v2/content/types?offset=5&limit=3' 

The specs are from https://github.com/ezsystems/ezpublish-kernel/blob/master/doc/specifications/rest/REST-API-V2.rst#list-content-types
JIRA link: https://jira.ez.no/browse/EZP-21681

Work in progress for the orderBy.