Make Klass names configurable

[nirebu]

It can happen that a user has already configured some klasses on their Kustomer organization, and given that they cannot be renamed or edited easily, it could be useful to make the relationship between Solidus classes and Kustomer Klasses configurable.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It might be closed if no further activity occurs. Thank you for your contributions.