feat(gnoweb): disable html in markdown

[alexiscolin]

In line with our vision for a HTML-free Gnoweb, this PR disables the rendering of HTML within Markdown content. It replaces all elements recognized as HTML tags (e.g., <div>, <br>, <web-component>) with empty spaces before sending the content to the front-end. The parsing still happens via JavaScript, but now without any HTML tags. However, HTML tags like `<div>lorem ipsum</div>` can still appear within code blocks in Markdown, as usual, but won’t be parsed/read as actual HTML.

Additionally, this feature is controlled by the gnoweb boolean flag with-html, which defaults to false.

cc @gfanton

Warning

Enabling this feature will break the design of gno.land realms (and any other realms relying on HTML), since current layout elements like columns, stacks, or jumbotrons... are built with HTML. We will need to adopt the new design system expected with gnoweb2.0 (or future gnoweb1 improvements).

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[codecov]

Codecov Report

Attention: Patch coverage is 42.85714% with 12 lines in your changes missing coverage. Please review.

Project coverage is 63.07%. Comparing base (f6bd2d3) to head (4aaf19d).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
gno.land/pkg/gnoweb/gnoweb.go	40.00%	9 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2964      +/-   ##
==========================================
- Coverage   63.08%   63.07%   -0.01%     
==========================================
  Files         563      563              
  Lines       79254    79273      +19     
==========================================
+ Hits        49998    50005       +7     
- Misses      25896    25904       +8     
- Partials     3360     3364       +4     

Flag	Coverage Δ
contribs/gnodev	60.62% <ø> (ø)
contribs/gnofaucet	15.77% <ø> (+0.94%)	⬆️
gno.land	67.46% <42.85%> (-0.10%)	⬇️
gnovm	67.25% <ø> (ø)
misc/genstd	79.72% <ø> (ø)
misc/logos	19.45% <ø> (ø)
tm2	62.25% <ø> (-0.01%)	⬇️

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[moul]

This is the way.

[albttx]

I just checked my r/albttx/home render, Could you also fix <img alt="desc" src="url" > into ![desc](url),

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ps: It's cool that you kept the options with a --with-html flags :)

[alexiscolin]

@albttx Thank you for the additional tests! I really appreciate :)
I understand your point but translating HTML to Markdown would go against our ultimate goal of avoiding HTML in realms. The focus should be on enhancing Markdown itself to handle the use cases where HTML is currently needed, keeping things consistent and avoiding the introduction of HTML into realms. If we fix HTML, we still promote it in a way.