Support for a local-apply operation

[netomi]

Currently the apply operation does apply all changes between the configuration and the live settings.

However, when running the service as an app, it would be beneficial if we just apply the changes to the previous config as we already ensured that there is no drift wrt the live settings in the check-sync task.

This would speed up the apply and also prevent cases where some settings would potentially be overridden, so we could adjust the check-sync method as well and do not require it for PRs, speeding up the whole process and reducing the noise.