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>

src/meson.build

@@ -21,6 +21,8 @@ subdir('android')
 subdir('libcamera')
 subdir('ipa')
 
+subdir('lc-compliance')
+
 subdir('cam')
 subdir('qcam')