🔥 rework DIMState and DIMStateClient
@mdonze and @matteof this modification does have some side-effects on DIMStateClient, I've checked EACS and RawFileMerger, if you can think about clients using this class let me know.
- Both are now thread-safe
- DIMState::removeError/DIMState::removeWarning now return boolean values
- DIMStateClient does not throw exceptions on getActualValue when in ERROR
- errorSignal and errorReceived are called only on error (not called when service is in ERROR state anymore)
- noLink sets the service in "NOT READY"
- static consts added for NotReadyState and ErrorState