cubicweb-tracker #2793859 extend version ordering to support semantic versioning [in-progress]

Description can be found here: http://semver.org/

priorityimportant
typeenhancement
done in<not specified>
load0.500
load left0.500
closed by<not specified>
patch[version_sort_value stored procedure] New implementation of semantic versioning (closes #2793859). [in-progress][schema/_regproc.postgresql/ version_sort_value] New implementation according to the Semantic Versioning standard (2.0.0-rc.2 -- www.semver.org) [folded]