CFY-1373 refactor source/target context creation
CFY-1373 refactor source/target context creation

cloudify-cosmo/cloudify-plugins-common,cloudify-cosmo/cloudify-plugins-common,isaac-s/cloudify-plugins-common,isaac-s/cloudify-plugins-common,isaac-s/cloudify-plugins-common,xdegenne/cloudify-plugins-common,cloudify-cosmo/cloudify-plugins-common,codilime/cloudify-plugins-common,codilime/cloudify-plugins-common,codilime/cloudify-plugins-common,geokala/cloudify-plugins-common