refactor: stop using deprecated Account.configure()

[link2xt]

No description provided.

[Hocuri]

BTW, this could use list_transports(), but it's fine not to do this now

[Hocuri]

This code is still in login_param.rs:

    /// Saves entered account settings,
    /// so that they can be prefilled if the user wants to configure the server again.
    pub(crate) async fn save(&self, context: &Context) -> Result<()> {

and it's still needed by UIs until they switch to a list-transports screen, so, I think we'll anyways need to keep these configs for a bit.

[link2xt]

Opened #7342

[Simon-Laux]

should we also do this for bots? https://github.com/deltachat-bot/echo

Ideally we would use add_transport_from_qr in the bots, right?

Or is that something for later, since deleting transports is not supported yet?
would transports to update/delete be identified by their email address?

[link2xt]

configure() is deprecated, so add_transport_from_qr should be used to add the first transport for accounts.

[Hocuri]

Ideally, bots will also use add_transport_from_qr() or add_or_update_transport().

BUT, we will probably need to keep around configure() for quite some time (possibly years) in order not to break all existing bots. So, it's not very urgent; it doesn't matter whether we start transitioning bots now or in a few months.