Add basic translation support

.gitmodules

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+[submodule "strings"]
+	path = strings
+	branch = main
+	url = https://github.com/byecorps/id-strings

common/strings.php

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+<?php
+
+function get_string($key="generic.generic") {
+    global $LANG;
+
+    $key_path = explode('.', $key);
+
+    $result = $LANG;
+
+    foreach ($key_path as $k) {
+        if (isset($result[$k])) {
+            $result = $result[$k];
+        } else {
+            return $key;
+        }
+    }
+
+    return $result;
+}
+
+function patch_lang($lang="en") {
+
+    global $LANG, $DOC_ROOT;
+
+    $temp = $LANG;
+
+    if (file_exists("$DOC_ROOT/strings/$lang.php")) {
+        require_once("$DOC_ROOT/strings/$lang.php");
+    }
+
+    function merge_arrays($original, $new) {
+        foreach ($new as $key => $value) {
+            if (is_array($value)) {
+                if (!isset($original[$key])) {
+                    $original[$key] = [];
+                }
+                $original[$key] = merge_arrays($original[$key], $value);
+            } else {
+                // Replace only if the value is not blank
+                if ($value !== '') {
+                    $original[$key] = $value;
+                }
+            }
+        }
+        return $original;
+    }
+
+    $LANG = merge_arrays($temp, $LANG);
+}

strings

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+Subproject commit 2ca0a987728cf7c90454eab06083f49442109eb5