[Feature] Unlimited zoom

[Beanow]

Currently there's a fixed limit to the zoom level.
https://github.com/JavaCafe01/PdfViewer/blob/d6d909859cbfdaa4180cc2ca387951122128cedb/app/src/main/java/com/gsnathan/pdfviewer/MainActivity.java#L265

It would be great to remove this limit, or add an option to disable it.

Why

I'm trying to view a high resolution (vector) public transport map, and the maximum zoom is nowhere near enough zoom. Most of the text isn't readable even if I squint my eyes, as it's intended for much more zoom.

[ferrum]

Hi, I forked this repo and added the functionality to zoom up to 10x instead of the default 5x.

10x is actually the maximum zoom that the underlying PDF library can handle. To increase this number, we should edit it.

You can find the relese of my fork here signed and ready to be installed.

Best regards.