* providers.Interface: rename ValidateDataSourceConfig to
ValidateDataResourceConfig
This PR came about after renaming ValidateResourceTypeConfig to
ValidateResourceConfig: I now understand that we'd called it the former
instead of the latter to indicate that the function wasn't necessarily
operating on a resource that actually exists. A possibly-more-accurate
renaming of both functions might then be ValidateManagedResourceConfig
and ValidateDataResourceConfig.
The next commit will update the protocol (v6 only) as well; these are in
separate commits for reviewers and will get squashed together before
merging.
* extend renaming to protov6
ff05362d51