Updates for 4.0.2 release.

A better example configuration for OIDCRedirectURI in the README.md
for the mod_auth_openidc image.

Updates for the COmanage Registry 4.0.1 release.

Updates for COmanage Registry 4.0.0-rc1 including updating
PHP to 7.3.30 and the Debian base to bullseye.

Update the documentation to reflect the release of COmanage
Registry version 3.3.3.

Update the COmanage Registry version for the 3.3.1 release.

Updates for the COmanage Registry 3.2.4 release.

Revert mod_auth_openidc to version 2.3.11 after finding with
that environment variables for claims are not being set the same in the
2.4.x series.

Updated to use version 2.4.04 of mod_auth_openidc and Debian buster as
the base.

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.

Fix bug when using the environment variable
COMANAGE_REGISTRY_ENABLE_PLUGIN to specify a comma separated list of
plugins to enable where the comma separated list was not parsed
correctly.

Update the base image tag from php:7.0-apache to php:7.0-apache-jessie
since php:7.0-apache now uses stretch as a base and the package
dependencies need to be evolved before just switching to stretch.

See https://github.com/docker-library/php/issues/620.

Added a modified .htaccess file that is COPY'd into the image from the
Dockerfile. The modified .htaccess file adds three RewriteRule lines
to add environment variables OIDC_CLAIM_NAME_GIVEN,
OIDC_CLAIM_NAME_FAMILY, and OIDC_CLAIM_NAME_MIDDLE if the standard
OIDC claims are asserted so that they can then be consumed during
an enrollment flow as the default value for a name entry such as
Name (Official, CO Person).

Add functionality to allow an environment variable to indicate that the
COmanage database schema should be updated (./Console/cake database).
This is helpful when deploying a new version of the code that does not
result in a change in the version number and so upgradeVersion does not
fire. An example of this scenario is when new code is introduced in the
develop branch but before a release happens.

Also add functionality to allow an environment variable to indicate that
a non-core plugin should be enabled.

Moved the registry build and all COmanage specific
environment varilables later in the Dockerfile template
so that more layers can be reused when changing
COmanage registry versions.

Changed layout so that /local is a symlink to
/srv/comanage-registry/local instead of the other way
around so that plugins can easily reference files under
/srv/comanage-registry/app such as the StandardController
view files add.ctp and edit.ctp.

The ServerName for Apache HTTP Server may now be injected
using the environment variable SERVER_NAME. If not injected
then the entrypoint scripts will attempt to determine the
value for ServerName from the X.509 certificate for HTTPS.

Since the Apache version used in the images is recent enough
that SSLCertificateChainFile is obsoleted removed the ability
to inject an explicit chain file and updated the documentation to
note that the intermediate CA signing certificates should be
included with the server certificate sorted from leaf to root.