Scope package to js-temporal organization and rename

The full name of the package should be @js-temporal/polyfill, so as not to
be redundant.
(The other stuff at the bottom is added by `npm init`.)

Author: ptomato

package.json

@@ -1,5 +1,5 @@
 {
-  "name": "temporal-polyfill",
+  "name": "@js-temporal/polyfill",
   "version": "0.0.0",
   "description": "Polyfill for Temporal",
   "type": "commonjs",
@@ -86,5 +86,17 @@
     "singleQuote": true,
     "bracketSpacing": true,
     "arrowParens": "always"
-  }
+  },
+  "directories": {
+    "lib": "lib",
+    "test": "test"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/js-temporal/temporal-polyfill.git"
+  },
+  "bugs": {
+    "url": "https://github.com/js-temporal/temporal-polyfill/issues"
+  },
+  "homepage": "https://github.com/js-temporal/temporal-polyfill#readme"
 }