Feature Request: Support PATCH Requests in the API

## Environment details:

- N/A (Cloud Service)

## Steps to reproduce the issue:

1. Create an Action (or another entity) via the AIO CLI or REST API
2. Find a necessary use case to update one or more properties, annotations or others on the action
3. The only option is now to PUT a new version of the action including it's code

## Provide the expected results and outputs:

The API should support sending a PATCH request in a well-understood format like JSON Patch (rfc6902):
http://jsonpatch.com/

Which has a Scalia implementation:
https://github.com/gnieh/diffson

For example you could send a PATCH request to `/api/v1/actions/[my-action` with the body:

```
[
{ "op": "replace", "path": "/properties/2", "value": {
"key": "SERVICE_HOST",
"value": "https://my-sevice.companygateway.io"
} }
]
```

## Provide the actual results and outputs:

Not Supported

## Additional information you deem important:

The issue names no files, tests, or implementation entry points; begin with the REST API action endpoint and its current PUT behavior. Review the requested RFC 6902 JSON Patch format and define completion as PATCH requests updating selected action properties without requiring a complete replacement.

Written by the indexing model from the issue text.