Minify, compress, and possibly tree-shake assets

[peekxc]

Possibly a generalization / duplicate of #1665

When I load a basic shiny app w/ the cache disable, the download size for shiny.js is ~1 MB

The size of the minified file (shiny.min.js) shipped in the package is only 435 KB (though it is not loaded in the default app); a minified and Brotli-compressed version would be a mere 78 KB.

It would be nice if you fixed the include to the minified one, and perhaps consider pre-compressing all the js/css assets for speedy loading

[schloerke]

No reason why we shouldn't be shipping shiny.min.js instead of shiny.js.

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Pre-compressing the files would be a new concept for the project. https://caniuse.com/brotli shows wide adoption of brotli. So it seems like a fair idea!

(We can not combine JS/CSS output files as html-dependencies could be overruled by another html-dependency definition. )

I see https://pypi.org/project/brotli-asgi/ , but it hasn't been updated for recent versions of python.

https://pypi.org/project/Brotli/ states version 3. So its a possibility