build: don't use local dependencies, and remove backend package: hatch doesn't support yet editable dependencies (https://github.com/pypa/hatch/issues/588), and to work on dev, backend and templates must be installed manually in dev mode. To avoid issues during sync when entering a shell, those dependencies are disabled and must be installed manually.

You'll find install instructions in documentation (see doc/installation.rst).

If you need help, come the Libervia official XMPP room: xmpp:libervia@chat.jabberfr.org?join or join us with a web browser via https://chat.jabberfr.org/converse.js/libervia@chat.jabberfr.org