allow users to replace connection urls to connect queues behind proxy

[qhuangd]

Motivation

TDMQ currently can only be accessed inside the same VPC. This PR allows users to set-up a proxy in front of it, and access it through proxy.

Modifications

Add PatchConnURL func(*url.URL) to pulsar.ClientOptions, which will allow users to modify physicalAddr before connecting

Verifying this change

• Make sure that the change passes the CI checks.

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (no)
• The public API: (yes)
• The schema: (no)
• The default values of configurations: (no)
• The wire protocol: (no)

The changes are backward-compatible, it's an additional and optional field to ClientOptions

Documentation

• Does this pull request introduce a new feature? (yes)
• If yes, how is the feature documented? (GoDocs)