Add support to retrieve team and environment

[MikeGoldsmith]

Which problem is this PR solving?

Adds support for retrieving a team name and associated environment given an API key. This is similar to the existing VerifyWriteKey and VerifyAPIKey functions, but also returns the environment. The library uses the 1/auth endpoint to retrieve this information.

Short description of the changes

• Create shared func to retrieve team to use 1/auth endpoint and also retrieve environment
• Update VerifyWriteKey and VerifyAPIKey to use new shared func
• Add GetTeamAndEnvironment func that uses the new shared logic
• Add unit tests to verify behaviour of all three functions