Exclude user-defined table types from generated CDS (or support them as CDS types)

[ThePlenkov]

Hi!

I just noticed that if we declare table type in the system like that:

it ends up in CDS like this:

if we'll try to select from such an entity - that will fail of course.

Therefore I propose for now just to exclude such user-defined types from the selection. And if needed to return the back already as CDS types.
Luckily we can simply filter out them with IS_USER_DEFINED_TYPE = FALSE

[jung-thomas]

Merged and delivered with 2.202105.9