[feat] [broker] support broker isolation for uniform load shedder strategy

[rdhabalia]

Motivation

We added Uniform load balancer strategy in #12902 which considers all the brokers and distributes the load uniformly across all available brokers. However, it doesn't consider namespace isolation policies where we want to uniformly distribute load across brokers which are part of same isolation group. This PR supports namespace isolation and distribute load across that subset of brokers based on their isolation group.

Modification

UniformLoadShedder prepares group of brokers which are part of isolation policy and try to find out bundle-candidate such a way it uniformly distributes load across that prepared group.

Result

UniformLoadShedder considers namespace isolation policy while distributing the load.

[github-actions[bot]]

@rdhabalia:Thanks for your contribution. For this PR, do we need to update docs? (The PR template contains info about doc, which helps others know more about the changes. Can you provide doc-related info in this and future PR descriptions? Thanks)

[github-actions[bot]]

@rdhabalia:Thanks for your contribution. For this PR, do we need to update docs? (The PR template contains info about doc, which helps others know more about the changes. Can you provide doc-related info in this and future PR descriptions? Thanks)

[Anonymitaet]

@rdhabalia for the doc side, will you add explanations here?

[rdhabalia]

@Anonymitaet it's just an internal handling and it will not require any additional documentation

[lordcheng10]

When the traffic to be unloaded is too small, there is no need to unload at this time to avoid unnecessary unload：https://github.com/apache/pulsar/pull/13140

[rdhabalia]

ping.

[rdhabalia]

@codelipenghui this PR was created 2 months back and ready to merge then why did you move to 2.11 release?

[rdhabalia]

this is not acceptable

[github-actions[bot]]

The pr had no activity for 30 days, mark with Stale label.

[github-actions[bot]]

The pr had no activity for 30 days, mark with Stale label.

[poorbarcode]

Since we will start the RC version of 3.0.0 on 2023-04-11, I will change the label/milestone of PR who have not been merged.

• The PR of type feature is deferred to 3.1.0
• The PR of type fix is deferred to 3.0.1

So drag this PR to 3.1.0

[github-actions[bot]]

@rdhabalia Please add the following content to your PR description and select a checkbox:

- [ ] `doc` <!-- Your PR contains doc changes -->
- [ ] `doc-required` <!-- Your PR changes impact docs and you will update later -->
- [ ] `doc-not-needed` <!-- Your PR changes do not impact docs -->
- [ ] `doc-complete` <!-- Docs have been already added -->