misc: update names for D-Bus service file and zsh autocompletion: - using `li` as main shortcut for `libervia-cli` instead of `jp` - fix outdated Python version in `_li` zsh completion shell - following global name change, D-Bus service file is no `org.libervia.Libervia.service` and it launches `libervia-backend`

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

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