Improve logging in tenanted container factory classes

When a tenanted container of any type (Cosmos, SQL, Gremlin, Storage) is created, configuration is read from the current tenant, firstly by looking for specific configuration for the container being created (based on the definition of the required container), then by looking for default configuration.

When tenants or applications are misconfigured, the outcome is generally unexpected and unhelpful exceptions. As such we need to dramatically improve the logging code around container creation (without leaking any secrets) so that it's easy to see in AppInsights what configuration is being used and where it points to (e.g. the names of keyvaults, databases, etc).

We also need to ensure we are throwing helpful exceptions when configuration is missing or invalid.