[Feature Request] Support JSON Patch, Diff and (especially) Merge Patch

As far I've seen, there is no support for JSON Patch, Diff and Merge Patch. Following [JSON Patch and Diff](https://json.nlohmann.me/features/json_patch/) and [JSON Merge Patch](https://json.nlohmann.me/features/merge_patch/) it is an proposed standard [RFC 6902](https://tools.ietf.org/html/rfc6902) and [RFC 7386](https://tools.ietf.org/html/rfc7386).
IMO, even the JSON merge patch has a practical use case: using a built-in JSON document for configuration/settings and having the user overwrite a small subset of it with a read-in configuration file from the filesystem. This in turn also allows dumping the default values to the filesystem for the user (or even the complete 'patched' settings).