Physical Ticket Printing: Filter, Bulk Download, and Print-Optimized PDFs

**Is your feature request related to a problem? Please describe.**
We currently lack the ability to efficiently fulfill physical ticket requests for customers who prefer to receive their tickets by mail. This limitation prevents us from catering to a segment of our audience and complicates the process of distributing physical tickets when required for certain events.

**Describe the solution you'd like**
We propose enhancing alf.io's admin interface with the following features:

1. A filter option to identify tickets that require physical printing, based on an additional service selection made during ticket purchase.
2. A bulk download feature to generate printable PDFs for all tickets matching the filter criteria.
3. Ensure the generated PDFs are optimized for printing on standard printers using special ticket paper stock.

This solution would allow event organizers to easily identify, generate, and print physical tickets for mail distribution using standard office equipment.

**Describe alternatives you've considered**
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**Additional context**
This feature would be particularly useful for events where physical tickets are preferred or required, such as certain music festivals, theater performances, or sports events. It would also cater to customers who may not have easy access to digital devices or prefer tangible tickets as souvenirs.