FR: Add the ability to test a specific range of pages

[F0rgenet]

Description

My test.typ outputs multiple pages (because it uses template), but i want to test only pages X-Z, not whole document.

Alternative Solutions

Add per-test configuration, that will make testing only specific range possible.

[tingerrr]

Sounds good, although I would generally recommend writing the template in a way that each part of the document can be tested individually.