This commit changes the method `ClusterInputs` to also take a default
deadline height. Previously, when calculating the default deadline
height for a non-time sensitive input, we would first cluster it with
other non-time sensitive inputs, then give it a deadline before we are
about to `sweep`. This is now moved to the step where we decide to
cluster inputs, allowing time-sensitive and non-sensitive inputs to be
grouped together, if they happen to share the same deadline heights.
This commit exports and renames the following variable names:
- `PendingInput` is now `PendingInputResponse` as it's responding to a
request.
- `pendingInput` is now renamed and exported as `SweeperInput`.
- `pendingInputs` is now renamed and exported as `InputsMap`.
This commit is first made from running:
```
gofmt -d -w -r 'PendingInput -> PendingInputResponse' .
gofmt -d -w -r 'pendingInput -> SweeperInput' .
gofmt -d -w -r 'pendingInputs -> InputsMap' .
```
And followed by some docs and variable names fixes.
This commit adds `BudgetAggregator` as a new implementation of
`UtxoAggregator`. This aggregator will group inputs by their deadline
heights and create input sets that can be used directly by the fee
bumper for fee calculations.
This commit makes the `ClusterInputs` directly returning the `InputSet`
so the sweeper doesn't know about the existence of `Cluster` interface.
This way we can have a deeper interface as the sweeper only needs to
interact with `Aggregator` only to get the final input sets, leaving the
implementation details being managed by `SimpleAggregator` and future
aggregators.
This commit refactors the grouping logic into a new interface
`UtxoAggregator`, which makes it easier to write tests and opens
possibility for future customized clustering strategies.
The old clustering logic is kept as and moved into `SimpleAggregator`.
