Add (unimplemented) config helper functions

libimagstorestdhook/src/vcs/git/config.rs

@@ -0,0 +1,11 @@
+pub fn commit_interactive(config: &Value) -> bool {
+    unimplemented!()
+}
+
+pub fn commit_message(config: &Value, action: StoreAction) -> Option<String> {
+    if commit_interactive(config) {
+        unimplemented!()
+    } else {
+        unimplemented!()
+    }
+}