release-notes: export meta data from conf.py and use in doc

Signed-off-by: Stephan Linz <stephan.linz@clondiag.com>
release-notes: set correct release string

Signed-off-by: Stephan Linz <stephan.linz@clondiag.com>
yocto-tutorial: export meta data from conf.py and use in doc

Signed-off-by: Stephan Linz <stephan.linz@clondiag.com>
yocto-tutorial: set correct release string

Signed-off-by: Stephan Linz <stephan.linz@clondiag.com>