Move fileUploadErrorMessage from Admin\Backend to Basic

Also removed the auto translate, return just string.
Is also a static method so can be called by
Basic::fileUploadErrorMessage too

Removed left over LANG settings in admin header

www/lib/CoreLibs/Basic.php

@@ -891,6 +891,42 @@ class Basic
 		return "<pre>".print_r($array, true)."</pre>";
 	}
 
+	/**
+	 * helper function for PHP file upload error messgaes to messge string
+	 * @param  int    $error_code integer _FILE upload error code
+	 * @return string                     message string, translated
+	 */
+	public function fileUploadErrorMessage(int $error_code): string
+	{
+		switch ($error_code) {
+			case UPLOAD_ERR_INI_SIZE:
+				$message = 'The uploaded file exceeds the upload_max_filesize directive in php.ini';
+				break;
+			case UPLOAD_ERR_FORM_SIZE:
+				$message = 'The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form';
+				break;
+			case UPLOAD_ERR_PARTIAL:
+				$message = 'The uploaded file was only partially uploaded';
+				break;
+			case UPLOAD_ERR_NO_FILE:
+				$message = 'No file was uploaded';
+				break;
+			case UPLOAD_ERR_NO_TMP_DIR:
+				$message = 'Missing a temporary folder';
+				break;
+			case UPLOAD_ERR_CANT_WRITE:
+				$message = 'Failed to write file to disk';
+				break;
+			case UPLOAD_ERR_EXTENSION:
+				$message = 'File upload stopped by extension';
+				break;
+			default:
+				$message = 'Unknown upload error';
+				break;
+		}
+		return $message;
+	}
+
 	// ****** DEBUG/ERROR FUNCTIONS ******
 
 	// ****** RANDOM KEY GEN ******