change sosa_shacl namespace

[pvgenuchten]

the url http://stko-kwg.geog.ucsb.edu/sosa-shacl/ does not resolve, is it an idea to update the url to:

https://knowwheregraph.github.io/kwg-shacl/sosa# or http://stko-kwg.geog.ucsb.edu/#sosa-shacl

and add the shacl to gh_pages branch