Fix/remove wdf report call in nhs api

[duncanc19]

Work done

• Changed NHS API endpoint to retrieve all data from Establishment table and add workers to the query
• Refactored database calls to ensure the same data was being returned for all workplace types

Reason

All of the data required for this endpoint is available in the Establishment and Worker tables. By using the wdfsummaryreport function, a table was being generated for all workplaces each time the endpoint was hit which seemed fine in staging but could have been a problem when there are large amounts of live data.

Tests

Does this PR include tests for the changes introduced?

• Yes
• No, I found it difficult to test
• No, they are not required for this change