input.properties - poor names for Authentication options

[DinoChiesa]

Summary

In the input.properties file , the options relating to authentication are misnamed.

• SOURCE_AUTH_TYPE - this is really a credential type, it is either a Token, or a Basic Auth blob. We should probably rename this to be SOURCE_AUTH_PREFIX, and the valid values should be Basic or Bearer. That would make it really clear what it is used for.
• SOURCE_AUTH_TOKEN - is really a credential. Sometimes the credential is a Token, and sometimes it is a basic Auth blob, which is not a Token. So I think kwe should rename this to be SOURCE_AUTH_CREDENTIAL.
• We could probably make some logic in python to default the SOURCE_AUTH_TYPE (SOURCE_AUTH_PREFIX) to the right thing, by just trying to base64 decode the blob. If it succeeds, then the auth prefix is Basic. If not, it's a Token, use Bearer.

Expected

The options for Authentication are appropriately named, and default to reasonable things.