Add scenario for migrating schema with all tables contained

[zhiweio]

Description of changes:

Add scenario for migrating schema with all tables contained.

Migrate single schema:

{
  "unloadSource": {
    "schemaName": "public"
  },
  "copyTarget": {
    "schemaName": "public"
  }
}

Migrate multiple schemas:

{
  "unloadSource": {
    "schemaNames": [
      "model",
      "public"
    ]
  },
  "copyTarget": {
    "schemaNames": [
      "model",
      "public"
    ]
  }
}

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