feat: move sample fixtures into sample subdir

fixtures/program/host.json

-[
-  {
-    "model": "program.host",
-    "pk": 1,
-    "fields": {
-      "name": "Musikredaktion",
-      "is_active": true,
-      "email": "",
-      "biography": "",
-      "image": null,
-      "created_at": "2000-06-01 00:00Z",
-      "created_by": "loaddata"
-    }
-  }
-]

fixtures/program/show.json

-[
-  {
-    "model": "program.show",
-    "pk": 1,
-    "fields": {
-      "predecessor": null,
-      "type": 3,
-      "funding_category": 1,
-      "name": "Musikprogramm",
-      "slug": "musikprogramm",
-      "image": null,
-      "logo": null,
-      "short_description": "Unmoderiertes Musikprogramm",
-      "description": "Unmoderiertes Musikprogramm",
-      "email": "musikredaktion@helsinki.at",
-      "cba_series_id": null,
-      "default_playlist_id": null,
-      "is_active": true,
-      "is_public": false,
-      "hosts": [
-        1
-      ],
-      "owners": [],
-      "language": [],
-      "category": [],
-      "topic": [],
-      "music_focus": [],
-      "created_at": "2000-06-01 00:00Z",
-      "created_by": "loaddata"
-    }
-  }
-]