search-blitz: generated queries for dogfood

Created by: keegancsmith

We want to run search blitz on dogfood. However, we need to adjust the queries since we want to target the gigarepo instead of the megarepo. This commit adds logic to generate the queries from the cloud queries.

Why this approach:

• we test the output and can assert megarepo is not called.
• we can inspect the generated output in PRs.
• when we update queries_cloud.txt we will be told to think about dogfood.
• go test is already needed for the above, so can just use it instead of go generate.

Test Plan: unit tests