Add extra padding for zoomed in web pages

[BPerlakiH]

Fixes: #885

Origin

I have found the zoom functionality is applying a JS callback to adjust the CSS values of the page:

kiwix-apple/Views/BuildingBlocks/WebView.swift

Lines 213 to 220 in c0539cc

	extension WKWebView {
	func adjustTextSize(pageZoom: Double? = nil) {
	let pageZoom = pageZoom ?? Defaults[.webViewPageZoom]
	let template = "document.getElementsByTagName('body')[0].style.webkitTextSizeAdjust='%.0f%%'"
	let javascript = String(format: template, pageZoom * 100)
	evaluateJavaScript(javascript, completionHandler: nil)
	}
	}

Proposed solution

I tried adjustments on the the swift view level, but that did not look good.

Therefore, I am proposing to adjust the webkit padding in a similar fashion as the text size increase is done for zooming in.

As of my testing it looks good on all devices (iPhone, iPad, macOS).

[kelson42]

I don't think this is a good idea at all to modify the css or dom. Why do we do that?

[BPerlakiH]

This was the implementation of the "page zoom" functionality.

[kelson42]

@BPerlakiH There should be some kind of zoom provided by the html widget itself

[BPerlakiH]

We have the default pinch gesture to zoom:

pinch_to_zoom.mov

[kelson42]

pinch is not what we need or talk about here!

[BPerlakiH]

We have the "magnify" option for the webView, but that zooms in a similar fashion as the pinch zoom, making the letters relatively larger, but you need to scroll horizontally as well to read it.
With the current solution the margins remain nicely in place, and the text wraps at the side of the screen.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.

Project coverage is 39.96%. Comparing base (99356e3) to head (b6ac11d).

Files	Patch %	Lines
Model/Utilities/Javascript.swift	0.00%	5 Missing ⚠️
Views/BuildingBlocks/WebView.swift	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #887      +/-   ##
==========================================
- Coverage   40.00%   39.96%   -0.05%     
==========================================
  Files         108      109       +1     
  Lines        6186     6193       +7     
==========================================
  Hits         2475     2475              
- Misses       3711     3718       +7     

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[BPerlakiH]

Converted to draft, as it's a stale PR / issue.