Constructs a WsUsernameTokenScs object for use with a!wsConfig. This object will cause the credentials to be retrieved from the secure credentials store at runtime.
See also: Secure Credentials Store
a!wsUsernameTokenScs( systemKey, usePerUser)
systemKey (Text): The key of the corresponding external system in the secure credentials store. Credentials associated with this external system will be retrieved.
usePerUser (Boolean): If true, the current user's credentials for the external system will be used. If false, the system-wide credentials for the external system will be used.