lc-compliance: Add a libcamera compliance tool

Add a compliance tool to ease testing of cameras. In contrast to the
unit-tests under test/ that aims to test the internal components of
libcamera the compliance tool aims to test application use-cases and to
some extent the public API.

This change adds the boilerplate code of a simple framework for the
creation of tests. The tests aim both to demonstrate the tool and to
catch real problems. The tests added are:

 - Test that if one queues exactly N requests to a camera exactly N
   requests are eventually completed.

 - Test that a configured camera can be started and stopped multiple
   times in an attempt to exercise cleanup code paths otherwise not
   often tested with 'cam' for example.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Acked-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>

meson_options.txt

@@ -25,6 +25,11 @@ option('gstreamer',
         value : 'auto',
         description : 'Compile libcamera GStreamer plugin')
 
+option('lc-compliance',
+        type : 'feature',
+        value : 'auto',
+        description : 'Compile the lc-compliance test application')
+
 option('pipelines',
         type : 'array',
         choices : ['ipu3', 'raspberrypi', 'rkisp1', 'simple', 'uvcvideo', 'vimc'],