New webpage: Unit tests

[iskyOS]

We'd like to create a new webpage on the website, within the new 'solutions' page tree.

Meta:

• URL: sourcegraph.com/solutions/generate-unit-tests
• Title: Build unit tests with AI
• Description: "Cody generates unit tests with a single button click, making unit testing a matter of hours rather than days."

Design file + assets: https://www.figma.com/file/HawFaBocHLKdMVMJD5Gxxl/Integrations-page-template?type=design&node-id=632-7383&mode=design&t=219QSEU0GnKAoMyS-0

[gitstart-app[bot]]

Here is the GitStart Ticket for this issue: https://clients.gitstart.com/sourcegraph/3436/tickets/SGM-6891