Optimize JS bundles

[Eric Eastwood]

Related to #132

Bundle efficiency

Based on what I was seeing in #175 trying to get the bundles to work; I couldn't properly get the chunks working as I ideally wanted where each entry point would be bundled up with no chunks except for a vendor chunk that included hydrogen-view-sdk

And I know the current chunking makes entry-client-room-alias-hash-redirect.js inefficient by just making it small and pulling in a separate redirect-if-room-alias-in-hash chunk which seems completely unnecessary and could be bundled into itself without an extra import.

Any combination of manualChunks and experimentalMinChunkSize options I tried with Vite just didn't do the trick.

Also see https://vitejs.dev/guide/build.html#chunking-strategy

Bundle size

The bundles seem pretty big at the moment and there is probably lots of opportunity to prune things down. Are we even tree-shaking?

Hopefully in #175, we figure out how to minify the JS.

Dev notes

A way to visualize JS bundles:

• DevTools: A better to way to visualize your JavaScript, https://umaar.com/dev-tips/270-devtools-lighthouse-treemap/ (direct link to YouTube)

[Eric Eastwood]

From https://pagespeed.web.dev/analysis/https-archive-matrix-org/lcerqhz1xk?form_factor=mobile

Reduce unused JavaScript (1.05s estimated savings)

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript. LCP

URL	Transfer Size	Potential Savings
matrix.org 1st Party	179.0 KiB	163.5 KiB
/assets/AvatarVie….js(archive.matrix.org)	179.0 KiB	163.5 KiB
…node_modules/hydrogen-view-sdk/lib-build/hydrogen.cjs.js	159.3 KiB	148.5 KiB
…node_modules/@matrix-org/olm/olm.js	10.9 KiB	10.8 KiB
…node_modules/dompurify/dist/purify.js	5.6 KiB	2.6 KiB
…node_modules/off-color/cjs/index.js	0.9 KiB	0.7 KiB