Check_MK Werk 2486: Remove special handling for non-distributed-setups in WATO

ID: 2486 Title: Remove special handling for non-distributed-setups in WATO Component: WATO Level: 2 Class: New Feature Version: 1.2.7i3 The handling of the activation of changes of single site setups was completely different than the case where you have a distributed setup with more than one Check_MK site. In order to simplify code, documentation and user experiance this distinction now has been removed. A single-site setup now exactly looks like and behaves like a distributed setup with just one site. This has no influence on performance or security.