csvWriter Refactor

Refactor the `csvWriter` for responses-beta for optimization and performance.

### Current behaviour:
For each line to be written the file is:
1. opened
2. file content is read into memory
3. file content is searched through for specific value
4. line in appended
5. file is closed

### Ideal beahviour:
Data in batched and the file is opened and read into memory only once per response creation flow.