libcamera: Define a PixelFormat type for application-facing formats

Define a PixelFormat type as a simple typedef to an uint32_t. The usage
of a dedicated type creates a cleaner and more self-described API.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/meson.build

@@ -25,6 +25,7 @@ libcamera_sources = files([
     'message.cpp',
     'object.cpp',
     'pipeline_handler.cpp',
+    'pixelformats.cpp',
     'process.cpp',
     'request.cpp',
     'signal.cpp',