[ADD] l10n_es_edi_tbai: Basque country's TicketBAI

**TicketBAI features**

- Generation of XML documents for invoices
- Automatic signing of documents with certificates
- Sending XML to the appropriate tax agency's servers
- Parsing and storing their response
- Preserving the invoice signature chain integrity
- Displaying the TicketBAI QR code on the invoice PDF
- Downloading XSD files for local validation
- Test mode using tax agencies' test servers

**Supported accounting flows**

- Posting and canceling invoices
- Foreign and national customers
- Multi-currency
- Refunds (credit notes)
- Discounts
- Simplified invoicing

**Not supported accounting flows**

- Specific VAT regimes
- Handling of third-party invoices
- XML generation and EDI operations for vendor bills (Bizkaia LROE)
- Modelo 140 (Bizkaia LROE)
- Invoice batching (Bikzaia LROE)

closes odoo/odoo#109907

Signed-off-by: Josse Colpaert <jco@odoo.com>