Closes: #1102

This includes the generation of metadata for all hosted entities, even if there's more than one entity defined for a certain type (e.g. multiple SPs or multiple IdPs).

Still missing:

* Metadata converter moved to the admin module.
* Metadata lookup.
* Showing metadata for trusted entities.
* Downloading certificates.
* Move the "clear my discovery choices" link to the new user interface.

This builds and minifies CSS and a common JS bundle, as well as copy the relevant fonts. In order to build, we now need to run "npm run build" after installing the dependencies with "npm install".

- Add dependencies
- Change link in script postload, base.twig
- Add function in Script.js
- Delete postload block in metadata-converter.twig and call clipboard function on button click.