Added Polaris_AuthenticateTo() to allow use of an alternate API server.

[adamshapiro0]

No description provided.

[anathan]

This works. I would have perhaps considered making the API URL part of the context instead to avoid the "three strings" argument in authenticate to, but this functionally works.

[adamshapiro0]

I thought about that a bit. To do it, we would still need to create a setter to modify the context since ideally we don't want anyone to mess with it directly in case it changes in the future. Even then, it would either store const char*, which would only work if the caller guaranteed the string didn't go out of scope ever, or have to store a char array, which increases memory footprint. With const char*, if they user used a temp string (e.g., wanted to use sprintf() or something) and it went out of scope, future calls to Authenticate() to handle reconnects would crash.

I figured this was the clearest and safest solution, and it's consistent with the existing ConnectTo() call.