Ability to set the PDF export timeout value in the .env file

[jtee3d]

Describe the feature you'd like

Currently, the PDF export timeout is set to 15 seconds. It would be useful to have this modifiable in the .env file, as per issue #5111.

Describe the benefits this would bring to existing BookStack users

For large books, this would prevent Bookstack from timing-out before the PDF is generated.

Can the goal of this request already be achieved via other means?

Yes, by modifying line 89 in /app/www/app/Entities/Tools/PdfGenerator.php

Have you searched for an existing open/closed issue?

• [X] I have searched for existing issues and none cover my fundamental request

How long have you been using BookStack?

3 months to 1 year

Additional context

No response