feat: add user edge to audit mixin, move to schema directory

[golanglemonade]

• Moves the AuditMixin, currently located in entx, to be in schema due to the dependency on the User schema
• Changes the updatedBy and createdBy fields to updatedByID and createdByID
• This allows us to use updatedBy as the edge field to pull the user details (e.g. email, first and last name)
• Also changed the deletedBy field to deletedByID to align with the other fields. This does not include an edge because it will not be retrievable by the API.
• The seed data needed to be adjusted because system (and unknown in the mixin) are not valid FK to the user table

go run cmd/cli/main.go procedure get  -z json         
{
  "procedures": {
    "edges": [
      {
        "node": {
          "background": "",
          "createdAt": "2025-01-04T12:49:55.986182-07:00",
          "createdBy": {
            "email": "[email protected]",
            "firstName": "matt",
            "id": "01JGSDTR8GFQGH3JQ2ECN22J45",
            "lastName": "anderson"
          },
          "createdByID": "01JGSDTR8GFQGH3JQ2ECN22J45",
          "description": "",
          "id": "01JGSDVYMCG3SHPZ7EHCGVJDQD",
          "name": "Onboarding SOP",
          "procedureType": "",
          "purposeAndScope": "",
          "satisfies": "",
          "status": "",
          "updatedAt": "2025-01-04T12:49:55.980409-07:00",
          "updatedBy": {
            "email": "[email protected]",
            "firstName": "matt",
            "id": "01JGSDTR8GFQGH3JQ2ECN22J45",
            "lastName": "anderson"
          },
          "updatedByID": "01JGSDTR8GFQGH3JQ2ECN22J45",
          "version": "v0.1"
        }
      }
    ]
  }
}