Add some easy way to install

I know that this should be done using some sort of build system (like meson), but the player is still far from finished and a basic install script should be sufficient for the time being, if anyone wishes to test it.

bin/clapper

@@ -0,0 +1,12 @@
+#!/usr/bin/gjs
+
+const Package = imports.package;
+
+Package.init({
+  name: "clapper",
+  version: "0.0.0",
+  prefix: "/usr/local",
+  libdir: "/usr/local/lib",
+  datadir: "/usr/local/share",
+});
+Package.run(imports.main);