fix: add system_id to station_status, set rental_app as nullable, set gbfs ttl and definition file

Co tenhle MR dělá? / What does this MR do?

Upravuje zpracování a výpis GBFS na základě otestování https://gitlab.com/operator-ict/golemio/projekty/oict/p0131.-data-pro-intermod-ln-naviga-n-syst-m/-/issues/23#note_887242948

Related issues

https://gitlab.com/operator-ict/golemio/projekty/oict/p0131.-data-pro-intermod-ln-naviga-n-syst-m/-/issues/23

Developer checklist

• Ensure this change works
• Write unit tests for this change as needed
• Update the OpenAPI document if exists
• Ensure CI/CD pipeline passes
• Create or update the implementation documentation if necessary
• Include a changelog entry
• Request a review