[improve][broker]Part-2 of PIP-433 add validation when enabling namespace-level Geo-Replication

[poorbarcode]

Motivation

This is part-2 of PIP-433.

Modifications

Checks compatibility between two clusters when enabling namespace-level replication, which includes the following

• All topics’ partitions that have been created should be the same
• Auto-creation policies between both clusters should be the same, including broker-level and namespace-level.

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

[Denovo1998]

@poorbarcode
1.Partition consistency verification is "one-way" (only starting from the local topic).

• The current logic will not detect the situation where "the remote already has a topic (and it may conflict with the local one in the future) but the local hasn't been created yet."
• The test does not cover the case where "topic only exists remotely and conflicts with local policy".

2.Performance risk: Calling getPartitionedTopicMetadataAsync remotely once for each topic under the namespace

Should we consider concurrency limiting (semaphore), batching, or state in the document/comments that this is an admin operation and may take time?

[lhotari]

Should we consider concurrency limiting (semaphore), batching, or state in the document/comments that this is an admin operation and may take time?

This is the biggest concern I have about this chance.