perf(gatsby): add a way to skip tracking inline objects

[axe312ger]

Description

While upgrading gatsby-source-contentful to its new version, we figured out that Gatsby is parsing JSON and Rich Text fields for references, while the plugin does handle these on its own.

In discussion with @pieh, we decided to implement a flag into Gatsby, which prevents nodes from being parsed for trackable inline objects. This is a huge performance improvement for the new gatsby-source-contentful version, while potentially providing a performance improvement to all other plugins that implement external data and/or handle references on their own.

Documentation

Nodes will get an additional, optional internal boolean property: node.internal.dontTrackInlineObjects.

By default, none of Gatsbys behavior will change. Plugin developers and users implementing their own node types have to opt into this features manually.

Tests

@todo this PR still lacks tests

Related Issues

#30855

[axe312ger]

I would guess we can skip this and I overlooked an already exported type for https://github.com/gatsbyjs/gatsby/pull/38805/files#diff-2a342b3e927ced0bfb4d19fe7f56ef73e0f08094f83526aaccc252d29af11870R44

🤔

[pieh]

We don't really have good types for schema customization - most of it is ... any 🙈 so this is fine

[pieh]

Minor NIT is we probably shouldn't use dontX in internal field names - it made some sense in our initial conversation when we considered graphql directive (@dontX similar to @dontInfer), but when talking about raw nodes - we probably should just say trackInlineObjects: false and do explicit checks (if (node.internal.trackInlineObjects === false)) (as it would be falsy by default)

EDIT: this can stay as-is for now, while I gather feedback from other folks (just to avoid busy work with unnecessary renames in case we would have to drop this idea alltogether) - so this can wait before being addressed (and just in case I can do that as well later on)

[pieh]

This will need to be updated before the release once it's clear that Gatsby Version that will contain the addition.

For now it will mean that users will have to use gatsby@ctf-next (once new wave of canary is released that include this change) - so maybe temporarily we can use that version there whatever that will end up being?

[pieh]

Thanks for the new toggle!