Chore: Move object type files to core

[madsrasmussen]

Description

These files are a leftover from when a relation type was editable from the UI. They aren't used anywhere but they are unfortunately exported. They are currently under "packages" but aren't set up as a package. I have moved them to the core package until they can be deleted. They have their own import map entry so it won't affect imports.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [x] Chore (minor updates related to the tooling or maintenance of the repository, does not impact compiled assets)