Add the config changes to handle CHT communication with the mediator

[njogz]

Description

This adds the relevant config changes required for the CHT to handle communication with the mediator for the loss to followup workflow.

Closes medic/interoperability#13

Code review checklist

• [ ] Readable: Concise, well named, follows the style guide, documented if necessary.
• [ ] Documented: Configuration and user documentation on cht-docs
• [ ] Tested: Unit and/or e2e where appropriate
• [ ] Backwards compatible: Works with existing data and configuration or includes a migration. Any breaking changes documented in the release notes.

License

The software is provided under AGPL-3.0. Contributions to this project are accepted under the same license.

[njogz]

This looks like a large PR but I have highlighted the relevant sections in comments. This config is based on the CHT's default config so a majority of the files in this PR are just clones of that.

[andrablaj]

Thank you for the updates @njogz! I tested the changes and I confirm that the config was uploaded successfully, without any extra action or file change from my side.

Please address my README suggestions above before I can review the PR.

[njogz]

@lorerod I will go ahead and merge this without your AT because @andrablaj has tested and I know you are busy with other testing work.