feat: add bucket quota command and bucket-level tag support

[overtrue]

Summary

• add new top-level rc quota command with set/info/clear for alias/bucket
• extend rc tag to support both bucket paths (alias/bucket) and object paths (alias/bucket/key)
• add Admin API quota methods and S3 bucket-tagging methods in core/s3 layers
• update command overview and test matrix docs

Validation

• cargo fmt --all
• cargo clippy --workspace -- -D warnings
• cargo test --workspace

Refs rustfs/rustfs#1925

[Copilot]

Pull request overview

This PR adds bucket quota management commands and extends tag support to work with both buckets and objects (previously only objects). The implementation spans multiple layers of the architecture, from core traits to CLI commands, following established patterns throughout.

Changes:

• Added new rc quota top-level command with set, info, and clear subcommands for managing bucket quotas via the Admin API
• Extended rc tag command to support both bucket paths (alias/bucket) and object paths (alias/bucket/key)
• Added bucket tagging methods (get_bucket_tags, set_bucket_tags, delete_bucket_tags) to the ObjectStore trait and S3Client implementation
• Added quota management methods to the AdminApi trait and AdminClient implementation

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
docs/TEST_MATRIX.md	Updated command list to include quota in optional commands
README.md	Updated command overview table to reflect bucket-level tag support and new quota command
crates/core/src/traits.rs	Extended ObjectStore trait with bucket-level tagging methods
crates/core/src/admin/types.rs	Added BucketQuota type with serialization test
crates/core/src/admin/mod.rs	Exported BucketQuota type and added quota operation methods to AdminApi trait
crates/s3/src/admin.rs	Implemented bucket quota Admin API methods (set/get/clear)
crates/s3/src/client.rs	Implemented bucket tagging methods, refactored tag building into shared function with proper error handling
crates/cli/src/commands/tag.rs	Refactored to support both bucket and object paths with TagTarget enum, improved code organization
crates/cli/src/commands/quota.rs	New command module implementing quota management with size parsing, human-readable formatting, and tests
crates/cli/src/commands/mod.rs	Integrated new quota command into CLI command routing

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