Schema Editing API refinements

[StefanApfel-Bentley]

• Utils get exported as DifferenceUtils namespace to reduce the exported api
• Differences use actual contextual property instead of generic path (like propertyName, constraint, enumerator)
• Schema Conflict Code now has prefix SchemaConflict instead of C

[mergify[bot]]

This pull request is now in conflicts. Could you fix it @StefanApfel-Bentley? 🙏 To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

[StefanApfel-Bentley]

This PR contains a couple of changes that seem to be useful (like the contextural conflict interfaces) others might break existing consumers (eg when changing the conflict codes) so, before this will continue, we should contact existing consumers of that api (like transformation).

[StefanApfel-Bentley]

I converted the PR as draft, since we won't work on that in the short future.