Cleanup left-overs from new UI migration

[benoit74]

Before releasing 4.0, we should cleanup left-overs from the migration:

• most code in scraper/src/gutenberg2zim/templates is now unused
• scraper/get_js_deps.sh
• GUTENBERG_STRUCTURE.md and scraper/docs/JSON_FILE_STRUCTURE.md files were more a reference for the migration ; I however feel like most info is very relevant and could definitely help a newcomer ; I'm just a bit worried about its maintenance ; either we clean it a bit (hoping it will be maintained ... not sure at all about that) or we simply remove it (which is a bit sad to loose such info ... but could easily be rebuild with AI)
• maybe other bits I forgot

[VikramAditya33]

About the markdown files GUTENBERG_STRUCTURE.md and scraper/docs/JSON_FILE_STRUCTURE.md, these are super detailed and could be really helpful for future contributors to understand the architecture. They document the design decisions and patterns pretty well. What do you think, keep them as historical documentation (maybe add a note that they're from the migration), or remove them? I'm leaning towards keeping them since they explain a lot of the "why" behind the current structure, but I can see the maintenance concern you mentioned.

Also locally i've removed:

• Old HTML templates (author.html, base.html, cover_article.html, Home.html, lcc_shelf.html, lcc_shelf_home.html)
• Old CSS files (Pure CSS, old styles, spinner, logo)
• Roboto fonts and Font Awesome
• jQuery and jQuery UI libraries
• Old JS utilities (l10n.js, tools.js)
• Unused icons and favicons
• get_js_deps.sh script

What do you think of this? I'll probably open a Pull Request so maybe you can understand a bit better

[benoit74]

As already mentioned, I feel like GUTENBERG_STRUCTURE.md and scraper/docs/JSON_FILE_STRUCTURE.md are indeed super useful, so I'm fine keeping them.