Added an LLM-based ETL example that adds the website for a given company.

[Etherdrake]

I created this tidy little program that takes in data about a company and tries to find the website (without web-search, this could make it far more effective). This example has been slimmed down to add just the company name where one request is made per company. I figured it would be cool to add it as an example.

I also added the missing documentation about how to install langchaingo :wink:.

PR Checklist

• [X] Read the Contributing documentation.
• [X] Read the Code of conduct documentation.
• [X] Name your Pull Request title clearly, concisely, and prefixed with the name of the primarily affected package you changed according to Good commit messages (such as memory: add interfaces for X, Y or util: add whizzbang helpers).
• [X] Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• [X] Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. Fixes #123).
• [X] Describes the source of new concepts.
• [X] References existing implementations as appropriate.
• [X] Contains test coverage for new functions.
• [X] Passes all golangci-lint checks.

[Etherdrake]

What exactly is the issue here? Still getting the same linter error.