Migrate to JSON i18n

Procedure per https://www.mediawiki.org/wiki/Manual:GenerateJsonI18n.php
with shim.

Change-Id: Ied3a4c392cf2ea16c6e858a1baaf9790db95e1f4

i18n/arc.json

@@ -0,0 +1,14 @@
+{
+    "@metadata": {
+        "authors": [
+            "334a",
+            "Basharh"
+        ]
+    },
+    "contributionscores": "ܦܠܛ̈ܐ ܕܫܘܬܦܘܝܬ̈ܐ",
+    "contributionscores-days": "{{PLURAL:$1|ܝܘܡܐ ܐܚܪܝܐ|$1 ܝܘܡܬ̈ܐ ܐܚܪ̈ܝܐ}}",
+    "contributionscores-allrevisions": "ܟܠ ܙܒܢ̈ܐ",
+    "contributionscores-pages": "ܦܐܬܬ̈ܐ",
+    "contributionscores-changes": "ܫܘܚܠܦ̈ܐ",
+    "contributionscores-username": "ܫܡܐ ܕܡܦܠܚܢܐ"
+}