A new VAT Books report is now available for Spanish accounting, helping businesses review and export VAT-related records more easily. The Spain reporting menu also now includes direct access to VAT Books and Libro Diario, with an added XLSX export option for the journal audit.

In this PR:
- Added 'VAT Books' report.
- Added 'Libro Diario XLSX' button in Journal Audit view (XLSX export).
- Introduced a dedicated submenu for Spain with:
  - 'Vat Books' report
  - 'Libro Diario' linking to the Journal Audit.

task-4831718