Add aria_custom_resource and related models

[davidfischer-ch]

Fix #8

• Custom Resource Core
• Properties
  • Core property attributes
  • Implement Default to/from API
  • Test Default
  • Integrate Properties to/from API inside Custom Resource to/from API
  • Test with some content (in custom resource acceptance test -> especially nil value (undefined) and other subtle edge cases)
  • Properties Ordering
  • Implement OneOf to/from API
  • Test OneOf
• CRUD Actions
  • Create Action
  • Read Action
  • Update Action
  • Delete Action
  • Make Update Action optional?
• Additional Actions 🚧
• Custom Form inside (tm) ...
• Update example in doc

Fix #18

• Resource Action

[Towl]

Hello,

Here is an example that could be useful: https://stackoverflow.com/questions/25182923/serialize-a-map-using-a-specific-order

[Towl]

And this : https://pkg.go.dev/gitlab.com/c0b/go-ordered-json

[davidfischer-ch]

I finally made it! Both unit and acceptances tests are showing that ordering of properties is preserved!