Move uriSchemes to *StoreConfig

It is a property of the configuration of a store --- how a store URL is
parsed into a store config, not a store itself.

Progress towards #10766

src/libstore/store-api.hh

@@ -216,6 +216,10 @@ public:
 
     virtual ~Store() { }
 
+    /**
+     * @todo move to `StoreConfig` one we store enough information in
+     * those to recover the scheme and authority in all cases.
+     */
     virtual std::string getUri() = 0;
 
     /**
@@ -897,7 +901,7 @@ struct Implementations
     {
         if (!registered) registered = new std::vector<StoreFactory>();
         StoreFactory factory{
-            .uriSchemes = T::uriSchemes(),
+            .uriSchemes = TConfig::uriSchemes(),
             .create =
                 ([](auto scheme, auto uri, auto & params)
                  -> std::shared_ptr<Store>