CVE-2024-23687: Hard-coded System User Credentials in Folio Data Export Spring module

The module creates a system user that is used to perform internal module-to-module operations. Credentials for this user are hard-coded in the source code. This makes it trivial to authenticate as this user, resulting in unauthorized access to potentially dangerous APIs, allowing to view and modify configuration including single-sign-on configuration, to read, add and modify user data, and to read and transfer fees/fines in a patron’s account.