libcamera: Move ipa includes to the same level as libcamera

The ipa includes are located in include/libcamera/ipa/. This gives an
incorrect impression that they are a sub-part of the rest of the
libcamera API, while they are the API towards the IPA the same way that
include/libcamera/ contains the API towards applications. To clarify
this, move them to include/ipa/.

The IPA headers are however still part of libcamera, so installing them
to ${prefix}/include/ipa/ would make little sense. To fix this, move the
application facing API to ${prefix}/include/libcamera/libcamera/ when
installed, and the IPA to ${prefix}/include/libcamera/ipa/. When major
versions of libcamera will be released, they could then be installed
side by side in ${prefix}/include/libcamera-${version}/.

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

Documentation/meson.build

@@ -21,6 +21,7 @@ if doxygen.found()
                   input : [
                       doxyfile,
                       libcamera_api,
+                      libcamera_ipa_api,
                       libcamera_headers,
                       libcamera_sources,
                   ],