Lists the secrets in the currently-selected vault.
Calling this method will fire the SecretList event once for each secret, and will also populate the Secret* properties.
If there are still more secrets available to list when this method returns, the SecretMarker property will be populated. Continue to call this method until SecretMarker is empty to accumulate all pages of results in the Secret* properties.
The MaxSecrets configuration setting can be used to control the maximum number of results to return at once.