Git provenance

Origin flow/engineering/engineering.yml 69:5
Uri engineering://nasdanika/modules/core/modules/flow/issues/git-provenance
Target Flow
Conversion of file URI's in markers to Git upstream URI's using jGit and then to URL's of, say, GitHub. Generic marker processing approach and then Git implementation with GitHub implementation as an extension. Would allow to navigate to the source location of model elements. Shall be very useful in the case of flow inheritance where elements may reside in multiple source repositories.