Use local or other cdn

[sverhoeven]

The haddock3 cli uses https://esm.sh to fetch the components. It would be nice to not depend on some 3rd party service. This could be accomplished by hosting the library on a bonvinlab server.

Alternatively we could maybe use a more used CDN like https://unpkg.com/ or https://www.jsdelivr.com/,

We will need to do our own bundling (our code + non-dev deps) whether we pick the bonvinlab server or another CDN.