Rename ContentType to EntityAccess for clarity and distinction from the Content module's usage of the same name/directory
source code formatting
add missing entity to installer
move `Tree` entity access methods to EntityRepository and refactor
rename Forums entity to Forum (entities are singular)
formatting
rename Posts to Posts (entities are singluar) and refactor as needed. Improved Post to use related entities and added convenience methods to obtain related entity ids where needed.
rename Topics to Topic (entities are singluar) and refactor as needed. Removed double entity defs Topics/Topic