Upgrade to Carbon Components Svelte v1.0.0

[n-peugnet]

This is a major change to Carbon Components Svelte as it also upgrades the Carbon stylesheet from v10 to v11. It is not released yet, but we can already try to see if anything breaks or if we will need to change some things.

See carbon-design-system/carbon-components-svelte#1614

Svelte projects consuming carbon-components-svelte will need to include SCSS preprocessors.

This is interesting as it will allow use to fix #58 in a proper way, as I imagined initially, by setting the $font-path parameter to an appropriate value. This in turn will allow to get rid of rollup-plugin-bundle-fonts introduced in 635ad42, and probably also the commonjs loader as I think it is the only non ES module of the project (and newer project are almost all ES modules).