Enhance ListDefinition provision - add discussion board validation

[SubPointSupport]

M2 should validate ListDefinition ensuring that discussion board list has content types enabled.
As per community feedback:

Requirement: Create a discussion board.
Thought that would be easy, but appeared to take some time. Things were not working, like views, and opening a discussion.
Turns out that you have to set "ContentTypesEnabled" to true on the listdefinition...

A list with template DiscussionBoard MUST have this set to true. It would be great to have this as a validation in SPMeta2?

https://www.yammer.com/spmeta2feedback/#/threads/inGroup?type=in_group&feedId=4881223