Update Use-Cases.md
Update Use-Cases.md

Update to the newest version of use cases, which aligns with the latest
blog:
https://www.alluxio.io/blog/alluxio-use-cases-overview-unify-silos-with-data-orchestration/

### What changes are proposed in this pull request?

Update to the latest version of use cases:

1. Use Case 1: Accelerate Analytics and AI in the Cloud
2. Use Case 2: Speed-up Analytics and AI for On-prem Object Stores
3. Use Case 3: “Zero-Copy” Hybrid Cloud Bursting
4. Use Case 4: Hybrid Cloud Storage Gateway for Data in the Cloud
5. Use Case 5: Enable Cross Datacenter Access

### Why are the changes needed?

The use case doc is outdated.

### Does this PR introduce any user facing changes?

No change.

pr-link: Alluxio/alluxio#14459
change-id: cid-51935699053abcc936e9f4d49f8281d271f894a4
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