docs: Bring/Setup documentation deployment for Federation from Server repo.

[abernix]

This brings the existing documentation and its supporting infrastructure (in
this case, modeled after/copied from the Apollo Server repository, but this
is standard "Apollo infrastructure" in the general sense) to the Federation
repository where it can live alongside the code that was migrated over in
#134.

Next Steps

⚠️ Each of these blocks the next, but neither of them blocks this PR from merging now as merging it would not result in the documentation becoming available in any linked-sense anywhere.

• Short-term solution to doc-set switcher (@StephenBarlow) (Tracked in Add Apollo Federation for the docset switcher gatsby-theme-apollo#147)
• Setup redirects from Apollo Server (@abernix) (Tracked in docs: Setup redirects to federation apollo-server#4565

Related: #142
Related: #143

(Both of these will close when the TODOs are completed).

[abernix]

@trevorblades Although apollo-server sets its Netlify base as docs/ and its publish directory as docs/public, that precise configuration over here (with what I believe is 100% the same structure) resulted in an Error cannot find /docs/docs/public.

Therefore, I had to introduce f69888a to this PR to make it build.

To be honest, having publish be relative to base makes a lot of sense to me — and that's exactly what the Netlify documentation suggests is the case — so I'm actually more surprised that apollo-server is requiring that treatment and happy that this makes sense, but it's odd that they're different. Perhaps Apollo Server's setup is grandfathered into a mode that requires relativity to the netlify.toml? Anyhow, just worth mentioning, and soliciting your perspective, not looking for anything to be changed necessarily (unless I'm doing something wrong!)

[trevorblades]

@abernix looks good to me! Regarding the relativity of the publish property in netlify.toml, I think you're right:

Perhaps Apollo Server's setup is grandfathered into a mode that requires relativity to the netlify.toml?

Tbh, reading the Netlify docs on this subject make me question how the other docs sites are working with their current configs, but I remember looking into this before, and coming to the same conclusion then. 🤷‍♂️

I'll coordinate with @StephenBarlow to get an update to the docset switcher into the docs theme 👍

[abernix]

Tbh, reading the Netlify docs on this subject make me question how the other docs sites are working with their current configs, but I remember looking into this before, and coming to the same conclusion then. 🤷‍♂️

@trevorblades Same.

I'll coordinate with @StephenBarlow to get an update to the docset switcher into the docs theme 👍

Thank you so much, to you both, in advance!