Remove hard dependency on meta-python

Set up the BBFILES_DYNAMIC variable to include meta-python and move all
python recipes to the corresponding dynamic-layers directory. This
prevents failures to parse recipes if meta-python is not available.

Fixes: QTBUG-113712
Change-Id: If26668e8d901c89be8527ff3951a00d739a89372
Reviewed-by: Samuli Piippo <samuli.piippo@qt.io>
(cherry picked from commit 16c7da9d10)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

conf/layer.conf

@@ -16,6 +16,8 @@ BBFILES += "${LAYERDIR}/recipes-*/*/*.bb ${LAYERDIR}/recipes-*/*/*.bbappend"
 
 # bbappends for optional layers
 BBFILES_DYNAMIC += " \
+    meta-python:${LAYERDIR}/dynamic-layers/meta-python/*/*/*.bb \
+    meta-python:${LAYERDIR}/dynamic-layers/meta-python/*/*/*.bbappend \
 "
 
 BBFILE_COLLECTIONS += "qt6-layer"