sculpt: add trace_logger as optional launcher

This patch adds the trace-logger utility to the default set of packages
along with an optional launcher. With this change, only two steps are
needed to use Genode's tracing mechanism with Sculpt:

- Add 'trace_logger' to the 'launcher:' list of the .sculpt file

- Either manually select the 'trace_logger' from the '+' menu,
  or add the following entry to the deploy configuration:

    <start name="trace_logger"/>

By default, the trace logger is configured to trace all threads
executed in the runtime subsystem and to print a report every 10
seconds. This default policy can be refined in the launcher's <config>
node. Note that the trace logger does not respond to configuration
changes during runtime. Changes come into effect not before restarting
the component.

Issue #4448

repos/gems/recipes/pkg/sculpt_distribution/archives

@@ -20,4 +20,5 @@ _/pkg/qt5_textedit
 _/pkg/mesa_gpu-cpu
 _/pkg/usb_webcam
 _/pkg/test-capture
+_/pkg/trace_logger
 _/pkg/mixer

repos/gems/sculpt/launcher/trace_logger

@@ -0,0 +1,23 @@
+<launcher pkg="trace_logger">
+
+	<route>
+		<service name="TRACE"> <parent/> </service>
+	</route>
+
+	<config verbose="yes"
+	        session_ram="90M"
+	        session_arg_buffer="1M"
+	        session_parent_levels="3"
+	        period_sec="10"
+	        default_policy="null"
+	        default_buffer="4K">
+
+		<policy label_prefix="init -> runtime -> "/>
+
+		<!-- uncomment to trace the drivers subsystem
+		<policy label_prefix="init -> drivers -> "/>
+		-->
+
+	</config>
+
+</launcher>