When closing a project, CloseResourceAction will check with registered
ModelProvider objects. This allows an Eclipse based product to e.g.
issue an extra warning should the project contain a running Java
program.

This change adds similar functionality to DeleteResourceAction, since
such is missing. Models can then validate not only a project close, but
also a project delete.

Change-Id: I9d908c35c9bbd81a69438b459ff3f02f63d6f67b
Signed-off-by: Simeon Andreev <simeon.danailov.andreev@gmail.com>