Split language ciw to ciw and ojb

A translatewiki translator said that this ojb the more
appropriate code for the existing translations, so it has
to be added. The code ciw is valid, too, so it's preserved.
The name "Ojibwemowin" is more appropriate for ojb, and
ciw is now named "Anishinaabemowin".

I also confirmed this with another Ojibwe language teacher.

For more reference, see downstream task:
https://phabricator.wikimedia.org/T281053

data/langdb.yaml

@@ -122,7 +122,7 @@ languages:
   cho: [Latn, [AM], Choctaw]
   chr: [Cher, [AM], ᏣᎳᎩ]
   chy: [Latn, [AM], Tsetsêhestâhese]
-  ciw: [Latn, [AM], Ojibwemowin]
+  ciw: [Latn, [AM], Anishinaabemowin]
   cjy: [cjy-hant]
   cjy-hans: [Hans, [AS], 晋语（简化字）]
   cjy-hant: [Hant, [AS], 晉語]
@@ -443,6 +443,7 @@ languages:
   ny: [Latn, [AF], Chi-Chewa]
   nys: [Latn, [PA], Nyungar]
   oc: [Latn, [EU], occitan]
+  ojb: [Latn, [AM], Ojibwemowin]
   oka: [Latn, [AM], n̓səl̓xcin̓]
   olo: [Latn, [AS, EU], livvinkarjala]
   om: [Latn, [AF], Oromoo]

data/language-data.json

@@ -732,7 +732,7 @@
             [
                 "AM"
             ],
-            "Ojibwemowin"
+            "Anishinaabemowin"
         ],
         "cjy": [
             "cjy-hant"
@@ -2857,6 +2857,13 @@
             ],
             "occitan"
         ],
+        "ojb": [
+            "Latn",
+            [
+                "AM"
+            ],
+            "Ojibwemowin"
+        ],
         "oka": [
             "Latn",
             [