test: make dandi-archive instance used for testing vendor configurable

Author: candleindark

dandi/tests/data/dandiarchive-docker/docker-compose.yml

@@ -36,9 +36,9 @@ services:
       DJANGO_DANDI_WEB_APP_URL: http://localhost:8085
       DJANGO_DANDI_API_URL: http://localhost:8000
       DJANGO_DANDI_JUPYTERHUB_URL: https://hub.dandiarchive.org
-      DJANGO_DANDI_INSTANCE_NAME: DANDI
-      DJANGO_DANDI_INSTANCE_IDENTIFIER: RRID:ABC_123456
-      DJANGO_DANDI_DOI_API_PREFIX: "10.80507"
+      DJANGO_DANDI_INSTANCE_NAME: ${DANDI_TESTS_INSTANCE_NAME:-DANDI}
+      DJANGO_DANDI_INSTANCE_IDENTIFIER: ${DANDI_TESTS_INSTANCE_IDENTIFIER:-RRID:ABC_123456}
+      DJANGO_DANDI_DOI_API_PREFIX: ${DANDI_TESTS_DOI_PREFIX:-10.80507}
     ports:
       - "127.0.0.1:8000:8000"