[beta5] Change/review the way the DSFR library is integrated and required

Problem/Motivation

The DSFR library is now removed from the ui_suite_dsfr source code and should be added/required through another manner.
The current code in 1.0-beta4 currently relies on a composer repository package defined the module composer.json. It contains a requirement to this defined package with the exact same non-standard name "gouvfr/dsfr".
this may not be the best way to achieve the requirement of DSFR, and this does not let people choose their way of including the library (for example using asset-packagist or another method...)

Steps to reproduce

Proposed resolution

Let's look at and iter over the different possible options and eventually move to another solution for its integration?
the corresponding documentation and clarifications would be necessary i guess.

I am open and available to contribute on this issue.

Remaining tasks

User interface changes

API changes

Data model changes