docs: point to "firebase.google" domain for hyperlinks in the usage section of README.md files (for the missing packages)

[nilsreichardt]

Description

#8814 was a draft pull request because it was just a proposal for a few packages 🙈

This PR is a proposal and should show a proof of concept for the new format. If this is a good solution, I will continue adding the links for the other packages.

This PR adds the links for the other packages.

cc: @russellwheatley

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[russellwheatley]

Thanks, @nilsreichardt. A few updates and it LGTM.