if CP users use cacertpath then include that in the context name (legacy CP users may still have context without cacertpath in the name but have cacertpath stored).

GetEnvWithFallback calls os.GetEnv() twice, once for the current var and once for the deprecated var.

Get login credentials using the functions from LoginCredentialsManager Functions are called in order and credentials are returned right away if found from a function without attempting the other functions.

Made it an interface so that we can inject MDS client for testing through GetMDSClient.