[UWS,TAP] Add clean release of all resources (e.g. Threads, Timers, DB...

[UWS,TAP] Add clean release of all resources (e.g. Threads, Timers, DB connections) allocated in a UWS and a TAP service. Small changes of the UWS API...but only if ExecutionManager, DestructionManager and UWS have been implemented by library users rather than using the default implementation.