Small performance improvements on mobile devices

[SvMak]

• replaced hero image from svg to webp;
• reducing DOM size.

Related to jhipster/generator-jhipster#27122

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[mraible]

I tried running the current site through https://pagespeed.web.dev:

Then, I tried the preview for this PR:

I'm not sure why the SEO went down. Maybe PageSpeed gets different information from Netlify vs. GitHub pages?

[SvMak]

Netlify is set to noindex

[mraible]

The main image on the homepage looks a little grainy with this PR. The current site has a much more crisp image, at least on my MacBook Pro.

[SvMak]

The main image on the homepage looks a little grainy with this PR. The current site has a much more crisp image, at least on my MacBook Pro.

@mraible Could you please check the latest changes?

[mraible]

The image looks better. Performance is 51 on mobile and 70 on desktop.

https://pagespeed.web.dev/analysis/https-deploy-preview-1382--jhipster-site-netlify-app/oatghbq1ev?form_factor=mobile

I was going to test our documentation archives to see what the old site's performance was. That's when I discovered our documentation archives are still using files from the main site. For example, see https://www.jhipster.tech/documentation-archive/v8.7.0/.

I've entered a new issue to track this. jhipster/generator-jhipster#27315

[SvMak]

The image looks better. Performance is 51 on mobile and 70 on desktop.

https://pagespeed.web.dev/analysis/https-deploy-preview-1382--jhipster-site-netlify-app/oatghbq1ev?form_factor=mobile

In preview mode Netlify added some third party scripts and this lowered the rating, in production version the rating should be higher.