Refactor unix domain socket store config (#11109)

Following what is outlined in #10766 refactor the uds-remote-store such
that the member variables (state) don't live in the store itself but in
the config object.

Additionally, the config object includes a new necessary constructor
that takes a scheme & authority.

Tests are commented out because of linking errors with the current config system.
When there is a new config system we can reenable them.

Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems>

src/libstore/local-binary-cache-store.hh

@@ -0,0 +1,21 @@
+#include "binary-cache-store.hh"
+
+namespace nix {
+
+struct LocalBinaryCacheStoreConfig : virtual BinaryCacheStoreConfig
+{
+    using BinaryCacheStoreConfig::BinaryCacheStoreConfig;
+
+    LocalBinaryCacheStoreConfig(std::string_view scheme, PathView binaryCacheDir, const Params & params);
+
+    Path binaryCacheDir;
+
+    const std::string name() override
+    {
+        return "Local Binary Cache Store";
+    }
+
+    std::string doc() override;
+};
+
+}