Add Cham languages (cja, cjm) (#384)

It's one of the languages requested at
https://phabricator.wikimedia.org/T304386
with all those scripts.

It's also configured on translatewiki, but was
never added to language-data properly.

Autonyms according to this dictionary:
Abdul Majid Hj. Yunos (2010). Kamus Cam–Melayu Jawi Rumi

data/language-data.json

@@ -924,6 +924,30 @@
             ],
             "Anishinaabemowin"
         ],
+        "cja": [
+            "cja-latn"
+        ],
+        "cja-arab": [
+            "Arab",
+            [
+                "AS"
+            ],
+            "چم فور"
+        ],
+        "cja-cham": [
+            "Cham",
+            [
+                "AS"
+            ],
+            "ꨌꩌ ꨚꨭꩉ"
+        ],
+        "cja-latn": [
+            "Latn",
+            [
+                "AS"
+            ],
+            "Cam pur"
+        ],
         "cjk": [
             "Latn",
             [
@@ -931,6 +955,30 @@
             ],
             "cokwe"
         ],
+        "cjm": [
+            "cjm-cham"
+        ],
+        "cjm-arab": [
+            "Arab",
+            [
+                "AS"
+            ],
+            "چم فاي"
+        ],
+        "cjm-cham": [
+            "Cham",
+            [
+                "AS"
+            ],
+            "ꨌꩌ ꨚꨰ"
+        ],
+        "cjm-latn": [
+            "Latn",
+            [
+                "AS"
+            ],
+            "Cam pai"
+        ],
         "cjy": [
             "Hant",
             [
@@ -5482,6 +5530,7 @@
             "Bali",
             "Batk",
             "Bugi",
+            "Cham",
             "Java",
             "Khmr",
             "Laoo",
@@ -6385,7 +6434,8 @@
             "kaa"
         ],
         "KH": [
-            "km"
+            "km",
+            "cja-latn"
         ],
         "KI": [
             "en"
@@ -7180,7 +7230,8 @@
         "VN": [
             "vi",
             "zh-hant",
-            "zh"
+            "zh",
+            "cjm-cham"
         ],
         "VU": [
             "bi",