feat: add delete organization and other removal operation functions

[shreddedbacon]

Checklist

• Affected Issues have been mentioned in the Closing issues section
• Documentation has been written/updated
• PR title is ready for inclusion in changelog

This adds new resolvers to support organizations:

• deleteOrganization - you could add one, now you can delete one
• removeDeployTargetFromOrganization - you could add one, now you can remove one
• removeProjectFromOrganization - you could add one, now you can remove one (it removes all groups and notifications from the project)

A bunch of new helpers were written to replace existing code and reduce some duplication.

[tobybellwood]

tested ok now