Upper bound the size of levelized buckets based on 1-level cuts

[SSoelvsten]

We can add a third constructor argument max_bucket_size to the levelized priority queue. Whereas the max_size can be computed by the (less precise) 2-level cut the max_bucket_size can be computed based on the 1-level cut instead.

• [ ] Add max_bucket_size constructor argument and deprecate the prior 2-argument constructor. In the old constructor set max_bucket_size to max_size
• [ ] Use max_bucket_size to instantiate each bucket instead.
• [ ] Extend the memory_usage function to also take the max_bucket_size into account (if possible).