issue: #46400
- add new server label rule.
- add `MILVUS_SERVER_LABEL_RESOURCE_GROUP` to determine the resource
group of querynode.
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## Summary by CodeRabbit
* **New Features**
* Automatic creation of resource groups when nodes with resource-group
labels join.
* Expanded server-label system supporting role-specific and global
labels.
* **Bug Fixes**
* Node acceptance now enforces resource-group name compatibility,
preventing cross-group assignment.
* **Refactor**
* Node handling flows updated to use richer node information for
assignment and validation.
* **Tests**
* Added tests validating resource-group labeling and node acceptance
behavior.
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settings.</sub>
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Signed-off-by: chyezh <chyezh@outlook.com>
1cae4a6194