Add stunnel container for Glance service

This patch creates a stunnel container for Glance service to perform
TLS termination.

Change-Id: I0743137577964f949eef949bad8163a990098bb0
Partially-Implements: blueprint add-ssl-internal-network

doc/source/matrix_aarch64.csv

@@ -78,6 +78,7 @@ sensu (deprecated),C,C,N,N,N,N
 skydive,N,N,N,N,N,N
 solum,N,C,N,C,N,C
 storm,C,C,C,C,N,C
+stunnel,C,C,C,C,C,C
 swift,C,C,C,C,N,C
 tacker,C,C,N,C,N,C
 telegraf,N,N,N,N,N,N

doc/source/matrix_x86.csv

@@ -80,6 +80,7 @@ sensu (deprecated),C,C,C,C,N,N
 skydive,C,C,C,C,N,C
 solum,N,C,N,C,N,C
 storm,C,C,C,C,N,C
+stunnel,C,C,C,C,C,C
 swift,C,C,C,C,N,C
 tacker,C,T,N,C,N,C
 telegraf,C,C,C,C,N,N

docker/stunnel/Dockerfile.j2

@@ -0,0 +1,15 @@
+FROM {{ namespace }}/{{ image_prefix }}base:{{ tag }}
+{% block labels %}
+LABEL maintainer="{{ maintainer }}" name="{{ image_name }}" build-date="{{ build_date }}"
+{% endblock %}
+
+{% block stunnel_header %}{% endblock %}
+
+{% import "macros.j2" as macros with context %}
+
+{% set stunnel_packages = ['stunnel'] %}
+
+{{ macros.install_packages(stunnel_packages | customizable("packages")) }}
+
+{% block stunnel_footer %}{% endblock %}
+{% block footer %}{% endblock %}

releasenotes/notes/add-stunnel-54c00678cd8aba08.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - Adds stunnel container image initially to provide ssl termination for
+    Glance (eventlet).