travis: set blank PIPENV_PYUP_API_KEY workaround

for `pipenv check` pyup.io safety check.

pyup.io recently removed the requirement for a custom
API key for pipenv's safety check, and, until an
upstream pipenv release can be delivered, this is the
suggested workaround. Previously, an error occured during
`pipenv check` since pipenv was using an API key.

See `https://github.com/pypa/pipenv/issues/4188`

.travis.yml

@@ -11,6 +11,7 @@ cache:
 env:
   global:
     - PIPENV_IGNORE_VIRTUALENVS=1
+    - PIPENV_PYUP_API_KEY=""
 install:
 - (cd manager && pipenv install --dev --deploy)
 - (cd orchestrator && pipenv install --dev --deploy)

orchestrator/orchestrator/views/registry/api.py

@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: MIT
+# (c) 2019 The TJHSST Director 4.0 Development Team & Contributors
+import traceback
+from typing import Tuple, Union
+
+from flask import Blueprint, current_app
+
+from ....docker.registry import get_registry_images
+from ..exceptions import OrchestratorActionError
+
+api = Blueprint("api", __name__)
+
+
+@api.route("/registry/api/images", method=["GET"])
+def get_registry_images_page() -> Union[str, Tuple[str, int]]:
+    """Returns Docker registry images.
+
+    Returns in JSON format.
+    """
+
+    try:
+        images = get_registry_images()
+    except OrchestratorActionError as ex:
+        current_app.logger.error("%s", traceback.format_exc())
+        return str(ex), 500
+    except BaseException:  # pylint: disable=broad-except
+        current_app.logger.error("%s", traceback.format_exc())
+        return "Error", 500
+    else:
+        return str(images)