JSONSchema validation of our config

[consideRatio]

The helm can validate a schema of the passed YAML values.

We should also support such schema validation for the configuration set via tljh-config. This validation can be done whenever the tljh-config command is used to configure something among other times.

The config file is located at /opt/tljh/config/config.yaml.

Related

• enabling https using letsencrypt results in not-trusted certificate from traefik #310 - likely avoided with schema validation
• Cannot prevent TLJH from creating new system users. #705 - likely avoided with schema validation

[jrdnbradford]

@consideRatio completed by #962 and can probably be closed.

[consideRatio]

❤️ 🎉 thank you for the help to keep things tidy @jrdnbradford and for the great work in #962!!!

Btw in case you didn't know, this could be made to autoclose on merge of #962 if its description included a note like "fixes #725" or "closes #725" for example.