Dynamic reload duplication config

## Feature Request
In PR #2000 , we can ignore cluster id with paramater `dup_ignore_other_cluster_ids`.
However, I think this function can be more flexible.
There is no doubt that, cluster id is very useful in multiple clusters duplication situation, backup-cluster can use it to judge data's priority.
So we may want to dynamic relod duplication config when we doing duplication.

**Describe the feature you'd like:**
Here is a case:
At beging, we have two clusters like cluster A dup data to cluster B. (A ----> B)
And now, demand changes:
C cluster also need to dup to cluster B. (A,C -----> B)
We don't need to restart the nodes on B, and can reload the config **ABOUT DUP**.

Start by reviewing PR #2000 and the dup_ignore_other_cluster_ids parameter to understand the existing duplication configuration. Trace how duplication configuration is loaded and applied, then define the reload behavior; done should allow adding cluster C to duplication into cluster B without restarting B's nodes.

Written by the indexing model from the issue text.