Added the django-request-logging package to mailman-web to assist when
necessary with debugging by being able to easily log the requests
recevied by the mailman-web service.

Added the MailHeaderMiddleware to settings.py for the mailman-web
service.

Directories on host should start with /srv/docker

Pin the upstream httpd image used for Mailman apache-shib to
version 2.4.38 so that he base is debian:stretch-slim.

Refactor the Shibboleth SP logging configuration so that default
shibd.logger, native.logger, and console.logger with details appropriate
for Docker images are in the base and can be easily copied into images.
Remove shibd.logger and native.logger from the COmanage Registry and
Mailman images as a result.

Updated the Mailman 3 for COmanage Registry images to
version 0.2.3 to pick up more recent version of
core (3.2.2), postorious (1.2.4), and hyperkitty (1.2.2).

Added the ability to inject the relayhost configuration for postfix.

Refactored the Dockerfiles and related
tooling to leverage Docker multi-stage build
functionality. Also updated base containers
to pick up later releases of Apache HTTP Server,
PHP, Shibboleth SP, and mod_auth_openidc.

Update the Mailman 3 images and service deployment scripts so
that Apache HTTP Server with the Shibboleth SP serves as the
web proxy so that the Mailman 3 UI interfaces (Postorius and
Hyperkitty) are protected with SAML.

Changes necessary to ingegrate COmanage Registry with Mailman 3.2.0.

Update Postfix entrypoint and main.cf configuration file to enable
injection of mynetworks configuration so that the proper networks may be
enabled or restricted.

Updated Mailman 3 Web Dockerfile to pin version numbers for various
django- modules. Updated settings.py configuration to remove all
social login providers. Updated login template file to remove links
to social providers.

Removed a hardcoded server name for the Mailman nginx configuration file
and replaced with logic to inject the server name based on environment
variable.

First commit of Mailman3 with REST API extensions needed for
provisioning from COmanage.