Allow export of a sitebndl.zip file

[richardhallett]

For production handle servers a sitebndl.zip is normally created within initial setup of a handle server, this is used to send to the handle org to allow for registering the handle server in production.

Because the docker handle server works based upon dynamic configuration, we need to be able to have this created and extractable from the docker handle server instance on demand.

Main challenges:

• Creating default admin public/private key files
• Building the zip from the server configuration
• A way for this to be extracted out of a running docker instance.

[tomascohen]

Are you still planning on working on this?
I believe we are still missing:

• contact information to add to the templates
• a way to detect the configuration has already been created (e.g. if you mount a volume to store those configs, it would be great to skip generating the configurations again) unless it is a design decision to create it every time.

[richardhallett]

We have no plans on making any changes to the docker handle server at present.
The issue was kept for possible future enhancement but it's not something we are going to be looking at any time soon.

The design decision to create the configs generated was to allow picking up of environment variables which is how we deploy the docker container within AWS ECS. This fitted our needs to avoid having to hardcode config files.
The generation happens everytime to make sure it picks up the appropriate ENV variables, however a possible improvement could be to change this to autodetect a mounted config directory too.