Add PartitionRegistry

[udaysagar2177]

Hi, do you think it is a good idea to have a PartitionRegistry that is capable of adding or removing Partitions during runtime? I can submit a PR based on our conclusion.

Based on the current code, the limit for a partition is just totalLimit * Partition#percentage. Now, as per controlled external config changes, I want to add or remove partitions from the limiter. When I add new partitions with adjusted percentages across the board, I want the current limit to be updated for existing partitions and get appropriate limits for new partitions. Similar case applies for when partitions are removed. This way I can evenly divide the quota and then pool it up when there are fewer actors.

[elandau]

Makes sense. Looking forward to seeing the PR.