Make ChannelSet immutable

Rewrite ChannelSet using GroupByHash as a template
Verify at least one worker is selected in scheduleFixedNodeCount
Change Input to integer in aggregations
Fix intellij warnings
Change LocalExecutionPlanner to use integer instead of Input
Remove Input class
Remove dead code
Add explicit Guice binder for jax-rs services
Remove support for sample weight from exact COUNT aggregation
Migrate HLL aggregations to new base class
Migrate approximate count distinct to new aggregation base class
Add method to define a default noop constructor
Fix intellij warning
Refactor new aggregation base classes to reduce code duplication
Remove BlockCursor from approximate COUNT(*)
Remove support for sampled data from percentile aggregations
Remove BlockCursor from CustomSum aggregation
Merge SimpleAggregationFunction and AbstractAggregationFunction