Find and replace all nolint instances refering to the `lll` linter and
replace with `ll` which is the name of our custom version of the `lll`
linter which can be used to ignore log lines during linting.
The next commit will do the configuration of the custom linter and
disable the default one.
In this commit the mission control based fee estimation
is supplemented with a payment probe estimation which can
lead to more accurate estimation results. The probing
utilizes a hop-hint heurisic to detect routes through LSPs
in order to manually estimate fees to destinations behind
an LSP that would otherwise block the payment probe.
Test stream cancellation of the TrackPayments rpc call. In order to achieve
this, ControlTowerSubscriber is converted to an interface, to avoid trying to
close a null channel when closing the subscription. By returning a mock
implementation of the ControlTowerSubscriber in the test that problem is
avoided.
