Converting BurstGPT workload to workload trace format

### 🚀 Feature Description and Motivation

Adding a workload generator that generate workload file based on BurstGPT workload trace format (e.g., csv file).

### Use Case

The generator should support converting BurstGPT traces to unified workload format, which later on consumed by AIBrix client to generate real-world workloads. [Link to workload.](https://github.com/HPMLL/BurstGPT/tree/main)

### Proposed Solution

Adding a generator that incorporates different adapter to convert trace files into LLM request workloads format. This issue tracks the converter of BurstGPT traces.