docs/Tips-and-Tricks: Include Formulae API in Homebrew caching proxy instructions

[colindean]

Expanded section on configuring Homebrew to use a caching proxy or mirror for both bottles and the Formulae API, including setup instructions.

• [X] Have you followed the guidelines in our Contributing document?
• [X] Have you checked to ensure there aren't other open Pull Requests for the same change?
• [X] Have you added an explanation of what your changes do and why you'd like us to include them?
• [ ] Have you written new tests for your changes? Here's an example.
• [ ] Have you successfully run brew lgtm (style, typechecking and tests) with your changes locally?

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[colindean]

In draft until I've proven it works once my Artifactory team livens the formulae API remote for me.