15x faster build time while using 49% less memory by migrating to Vite

[catFurr]

Switched from webpack to vite with minimal source code changes. This provides:

• significantly faster dev server start up time
• massive dx improvements. Everything is HMR, including scss, html, config, etc.
• HMR actually works inside meetings. No need for page reloads which were breaking the xmpp connection.
• Automatic cache invalidation. No need to manually update the version number anymore (still needed for lib-jitsi-meet)
• faster build times with lower memory usage. This can reduce CI/CD costs.
• built in SSI during dev/preview

Build metrics:

Tool	Avg Build Time	Avg Memory Usage
Webpack	150.26s	7.36 GB
Vite	9.87s (⚡ 15.2x faster)	3.72 GB (🎯 49% less)

Dev server metrics:

Tool	Avg Startup Time
Webpack	20.48s
Vite	5.16s (⚡ 4x faster)

Source code changes:

• replaced __filename with new URL(import.meta.url).pathname
• renamed index.web.js, VideoContainer.js, LargeVideoManager.js to JSX files.
• changed require to import
• updated worker imports to vite syntax.

Also tested with Rolldown-Vite and the improvements are even better.
3.66-second builds and 2.08GB memory usage
that's 41x faster than Webpack while using 72% less memory.

[catFurr]

This PR is almost ready, just need to test a few more things. I'm trying to keep this as a non-breaking change.

I created the draft PR to get some early feedback on this. Thanks!

[jitsi-jenkins]

Hi, thanks for your contribution!
If you haven't already done so, could you please make sure you sign our CLA (https://jitsi.org/icla for individuals and https://jitsi.org/ccla for corporations)? We would unfortunately be unable to merge your patch unless we have that piece :(.

[saghul]

This is really exciting, thanks for getting the ball rolling! It may take us a bit to review this, since we have no experience with Vite 😅