GSKit: Signature algorithm moved out of settings file

In GSKit V8.0, the default signature algorithm used when creating self-signed certificates or certificate requests or selected in the creation dialogs is passed as a command-line parameter. In GSKit V7.0, the default signature algorithm was specified in the settings file.

The change has very little effect: it causes a different default signature algorithm to be selected. It does not alter the selection of a signature algorithm.