Streamline exception types

This patch reduces the number of exception types by facilitating
globally defined exceptions for common usage patterns shared by most
services. In particular, RPC functions that demand a session-resource
upgrade not longer reflect this condition via a session-specific
exception but via the 'Out_of_ram' or 'Out_of_caps' types.

Furthermore, the 'Parent::Service_denied', 'Parent::Unavailable',
'Root::Invalid_args', 'Root::Unavailable', 'Service::Invalid_args',
'Service::Unavailable', and 'Local_service::Factory::Denied' types have
been replaced by the single 'Service_denied' exception type defined in
'session/session.h'.

This consolidation eases the error handling (there are fewer exceptions
to handle), alleviates the need to convert exceptions along the
session-creation call chain, and avoids possible aliasing problems
(catching the wrong type with the same name but living in a different
scope).

repos/base/include/trace_session/client.h

@@ -64,7 +64,8 @@ struct Genode::Trace::Session_client : Genode::Rpc_client<Genode::Trace::Session
 		/**
 		 * Retrieve subject directory
 		 *
-		 * \throw Out_of_metadata
+		 * \throw Out_of_ram
+		 * \throw Out_of_caps
 		 */
 		size_t subjects(Subject_id *dst, size_t dst_len)
 		{