Attempt To Honor Fit to 1-Page Height for Html/Pdf

[oleibman]

Fix #3266. Each sheet in a spreadsheet can specify that it be set to fit width or height to a fixed number of pages. Mpdf and most browsers already handle the common case of fit to 1 page wide; I am unable to find a solution for Dompdf or Tcpdf. Code is added for the common case of fit to 1 page high when possible; this will usually work in Mpdf, Dompdf, and most browsers. I am not able to come up with a way to handle fit to more than 1 page wide or high.

This is:

- [x] a bugfix
- [ ] a new feature
- [ ] refactoring
- [ ] additional unit tests

Checklist:

• Changes are covered by unit tests
  • Changes are covered by existing unit tests
  • New unit tests and samples have been added
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change
• Documentation is updated as necessary

Why this change is needed?

Provide an explanation of why this change is needed, with links to any Issues (if appropriate).
If this is a bugfix or a new feature, and there are no existing Issues, then please also create an issue that will make it easier to track progress with this PR.