Introduce 'nix store' command

src/nix/store.cc

@@ -0,0 +1,31 @@
+#include "command.hh"
+
+using namespace nix;
+
+struct CmdStore : virtual NixMultiCommand
+{
+    CmdStore() : MultiCommand(RegisterCommand::getCommandsFor({"store"}))
+    { }
+
+    std::string description() override
+    {
+        return "manipulate a Nix store";
+    }
+
+    Category category() override { return catUtility; }
+
+    void run() override
+    {
+        if (!command)
+            throw UsageError("'nix store' requires a sub-command.");
+        command->second->prepare();
+        command->second->run();
+    }
+
+    void printHelp(const string & programName, std::ostream & out) override
+    {
+        MultiCommand::printHelp(programName, out);
+    }
+};
+
+static auto rCmdStore = registerCommand<CmdStore>("store");