Entity Centre: narrow error reporting about whole entity exclusion

[jhou-pro]

Description

There are several situations where whole entity type is "excluded" from Domain Trees and thus can't be used in Entity Centres [and Web API queries]. In this case we get confusing unspecific error like the following:

Could not [un]check already 'excluded' property [entryDate] in type [SynRotableNote$$TgEntity_CB1E62745D28952F8D7C33D404F2A7BAD68BDDB466D1E7D8447FE37F7A2FC0A0].

This error shows that first property, added to Entity Centre result-set, is excluded. It would be better to indicate that whole SynRotableNote$$TgEntity_... entity type is "excluded" and why.

There are several reasons now why the type may be "excluded" fully:

1. entity type has abstract modifier
2. entity type does not have @KeyType annotation (there are compile time check on this now, however)
3. entity type has @DenyIntrospection annotation

Expected outcome

Narrower error reporting for Entity Centre runtime errors due to @DenyIntrospection annotation on a type.