ci(gitlabci): filter out docs src languages not declared in .i18n-filter file before build

docs/.gitlab-ci.yml

@@ -7,6 +7,8 @@ stages:
 .documentation-setup:
   before_script:
     - cd docs
+    - chmod +x ./scripts/i18n-filter.sh
+    - ./scripts/i18n-filter.sh
     - npm ci
 
 cache:

docs/scripts/i18n-filter.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+# This script deletes language files not declared in the .i18n-filter file
+
+set -e
+
+# Exit if the directory isn't found
+if [ ! -d $1 ]
+then
+    echo "$1 directory does not exist."
+    exit
+fi
+
+cd $1
+
+# Exit if the .i18n-filter isn't found
+if [[ -f .i18n-filter ]]
+then
+    # delete all languages not present in .i18n-filter
+    for i in *; do
+        if ! grep -qxFe "$i" .i18n-filter; then
+            echo "Deleting: $i"
+
+            rm -rf "$i"
+        fi
+    done
+else
+    echo "$1/.i18n-filter file not found!"
+    exit
+fi

docs/src/.i18n-filter

@@ -0,0 +1,4 @@
+public
+contributing
+getting-started
+index.md