Configuration fails if you don't instantiate factory before attempting to access config

In discussion of PR #64, @mwadams made this comment:

> this configuration all fails if you don't instantiate the factory before attempting to access the config.

See in situ:

https://github.com/corvus-dotnet/Corvus.Tenancy/pull/64#discussion_r376391941

TODO: this needs fleshing out because I don't yet understand what this really means, but we may need to review the design for all the providers.

Start with the discussion on PR #64, especially the linked comment, then trace how provider configuration is accessed before and after factory instantiation. No source files or tests are named; the work is done when the failure mode and expected provider configuration behavior are defined and the design review has a clear outcome.

Written by the indexing model from the issue text.