Explore move to ES modules (without transpilation)

[b-ma]

The template seems run well when type: module only with minor changes

possible steps to explore:

• [x] update template-build so that it transpile sources only if it finds type: module in the project package.json -> if it doesn't, add a post install
• [x] update soundworks-template, to use type: module
• [x] export server.js and client.js in soundworks so that the updates are even more simple and the import more elegant
• [ ] test on existing apps

This open the path for dynamic imports that could simplify a possible scaffolding tool

[b-ma]

https://github.com/sindresorhus/meta/discussions/15

[b-ma]

abandoned in v3, done in v4

• see https://www.npmjs.com/package/@soundworks/create for scafoolding tool