<!-- Thank you for submitting this PR! :) -->
## Description
Fix a bug which was causing an internal error when `null` was returned
by NDC for a field of array or object type.
### Product
_(Select all products this will be available in)_
- [x] community-edition
- [x] cloud
<!-- product : end : DO NOT REMOVE -->
### Type
<!-- See changelog structure:
https://github.com/hasura/graphql-engine-mono/wiki/Changelog-Guide#structure-of-our-changelog
-->
_(Select only one. In case of multiple, choose the most appropriate)_
- [ ] highlight
- [ ] enhancement
- [x] bugfix
- [ ] behaviour-change
- [ ] performance-enhancement
- [ ] security-fix
<!-- type : end : DO NOT REMOVE -->
### Changelog entry
<!--
- Add a user understandable changelog entry
- Include all details needed to understand the change. Try including
links to docs or issues if relevant
- For Highlights start with a H4 heading (#### <entry title>)
- Get the changelog entry reviewed by your team
-->
Fix a bug which was causing an internal error when `null` was returned
by NDC for a field of array or object type.
<!-- changelog-entry : end : DO NOT REMOVE -->
<!-- changelog : end : DO NOT REMOVE -->
V3_GIT_ORIGIN_REV_ID: 5c935ccd6720b5e5966dfa87c2e21dbb7a2b36f2
<!-- Thank you for submitting this PR! :) -->
## Description
This moves all the crates into a `/crates` folder. Everything appears to
just work, thanks Cargo!
V3_GIT_ORIGIN_REV_ID: 8e3ef287b1a46cabdb4d919a50e813ab2cddf8b1
