[DEV-14890] - New Download/v2/search endpoint

[DavidMikolaKC]

Description:

Currently the Advanced Search page allows for users to download either Awards with Subawards or Transactions with Subawards; never combining Awards and Transactions. A new endpoint is needed to support a new download modal that allows users to select which of the three they want. The /api/v2/download/search endpoint will power the downloads on the Advanced Search page and support Awards, Transactions, and Subawards.

Technical Details:

Requirements for PR Merge:

1. Unit & integration tests updated
2. API documentation updated (examples listed below)
   1. API Contracts
   2. API UI
   3. Comments
3. Data validation completed (examples listed below)
   1. Does this work well with the current frontend? Or is the frontend aware of a needed change?
   2. Is performance impacted in the changes (e.g., API, pipeline, downloads, etc.)?
   3. Is the expected data returned with the expected format?
4. Appropriate Operations ticket(s) created
5. Jira Ticket(s)
   1. DEV-14890

Explain N/A in above checklist: