Introduce custom plural rules

And enable gd locale

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/i18n/pluralRules/gd.ts

@@ -0,0 +1,11 @@
+export default function (choice: number): number {
+  if (choice === 1 || choice === 11) {
+    return 0;
+  }
+
+  if (choice === 2 || choice === 12) {
+    return 1;
+  }
+
+  return choice > 0 && choice < 20 ? 2 : 3;
+}

js/src/i18n/pluralRules/index.ts

@@ -0,0 +1,5 @@
+import gd from "./gd";
+
+export default {
+  gd,
+};