Remove auto-settle mode

[joostjager]

This issue serves as a place for discussing whether we should remove AutoSettle. It requires additional code paths, and arguably the added value is only in testing/development. The intended user group for lnmux is unlikely to need this functionality.

Alternatively it can be implemented in a script that subscribes to all payments via SubscribeInvoiceAccepted and automatically calls SettleInvoice for each of them.

[Torakushi]

Interesting idea!

Wouldn’t it useful for people that will use lnmux as a virtual node? (for inbound fees for example)
Maybe they won't want to rework their existing architecture to subscribe to lnmux events, but just use it as a virtual node

But for that, it is necessary to have a RPC call to retrieve all paid invoices (as there will be no settlement notifications).
(see this issue)