Custom plone/plone-backend images

These are custom Plone docker images.

They address some issues found in original plone/plone-backend images that are already merged but not released, and some others that are not merged yet.

The purpose of the repository is to have a public container registry in order to base our deployment images on them.

The generated docker images are:

• ghcr.io/codesyntax/plone-backend/server-builder
• ghcr.io/codesyntax/plone-backend/server-prod-config
• ghcr.io/codesyntax/plone-backend/plone-backend

The issues included here are:

Merged but not released:

• CLIENTHOME as env var: plone#177
• Add zopeuser command to docker-entrypoint plone#175 plone#178
• More configurable vars: plone#157

Unmerged:

• Do not do a find & chown for all files in /data: plone#172