Switch to schema-push model (rather than schema-pull)

[nickcampbell18]

Currently, the docs site pulls schema from different URLs at build time. This has a few consequences:

1. Occasionally it fails - Fail deployment when fetching of external documentation fails #157
2. I can't go back in Git history on this repo to see when a docs change was made
3. The GitHub action does not seem to rebuild the slug if the source sha has not changed (this might be a recent thing, but if you run the action it doesn't seem to do anything now)

I propose we switch to a schema-push model. I've used this successfully in the past - it's a more explicit workflow that allows better auditing of behaviour. It looks like this:

• Every repo which contributes schema has a GitHub action or CI job on the main branch.
• If their main branch passes, it pushes the relevant schema files into this repo (either directly onto the main branch or opening a PR, like this).
• When this repo build is green, it autodeploys.

Benefits of this approach:

1. If a build fails, we get a notification - the developer can then proactively fix their schema/docs
2. I can go back through Git history to see what the docs looked like at a particular time
3. Deployment is automatic - developers know that their schema will eventually be deployed (we could even have a Slack notification when it happens)

Downsides:

1. Main branch is very noisy with lots of automatic schema file changes

[nickcampbell18]

@jalyna thoughts? These are some reflections from explaining to @psteininger how the current system works

[jalyna]

@nickcampbell18 This is a really nice suggestion. This was the very first approach, when we only had one 2 Apps. So I think we should invest some time to improve this.

[nickcampbell18]

Do you have a preference for GitHub action vs CircleCI orb? I can probably bring across some of the code I wrote before to do this...

[psteininger]

No preference whatsoever. I think that whichever looks less complex to comprehend.

[jalyna]

I would believe that github actions might be easier here but just an assumption.