[UWS,TAP] Fix regression: the log message for the event REQUEST_RECEIVED was not displayed any more.

[UWS,TAP] Errors and log management improvements. Particularly, now TAP and UWS are able to manage correctly HTTP request abortions (i.e. when the user stop the request before the response has been fully sent, or when there is a connection problem or a time-out). Such abortions are considered by UWS and TAP merely as job abortion/cancel. No error is logged any more. In addition of this correction, log entries concerning the execution of a TAP sync/async job have been modified so that having more coherents messages. And stack traces of exception that occurred when executing a job (sync or async, tap or uws) are displayed just once: at the JOB END log entry, and not by the HTTP RESPONSE_SENT entry. And finally, output flush and interruption detection are made more often when writing a query result (the flush is particularly important when combining with fetch-size > 0 in synchronous mode....the sync response is then a streaming output).

[UWS] Add a log message filter: only messages whose the level is greater or equal to a given one are displayed. This level is by default DEBUG (meaning all messages are always written).

[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.

[UWS,TAP] Review some log messages (in the log file but also in the error summary of a job) ; particularly stack traces are added into the error summary, but are displayed just once in the logs.

[UWS,TAP] Review the exceptions and logs management + Add log file rotation (with a configurable rotation frequency)