Create a private test index with semantic capability in `azure-db`

## Description
The goal is to set up a private test index in Azure Search with semantic capabilities. This index should ensure that only clients on our private network have access to private documents.

## Tasks
- [x] Create a new index in Azure Search with semantic capabilities.
- [ ] #20
- [x] Populate the index with sample private documents.
- [ ] Implement tests to verify that only private finesse can access the documents. (Manual test)
- [ ] Document the setup and configuration steps.
- [ ] Review and validate the security measures in place.

## Acceptance Criteria
- A new semantic index is successfully created in Azure Search.
- Access to the index is limited to the specified private clients.
- Security tests confirm that no unauthorized access is possible.
- Documentation is complete and accurate.