[FEATURE] Add json_set function to PPL

[acarbonetto]

Is your feature request related to a problem?

As part of the RFC to add JSON functions, the json_set function would be useful to set or update elements of an existing json_object.

• META RFC: [META]Add PPL JSON extended functions support #3027
• PPL RFC: [RFC] Add PPL JSON extended functions support #3028
• Related Spark PPL PR: Support PPL JSON functions: construction and extraction opensearch-spark#780

What solution would you like?

### `JSON_SET`

**Description**

`json_set(doc, path, value [, path, value]...)` Updates existing or adds new json elements to a json document at the specified paths. Returns the updated document. 

**Arguments type:** JSON_OBJECT, STRING, STRING | JSON_OBJECT | JSON_ARRAY, ...

**Return type:** JSON_OBJECT

Example:

    os> source=people | eval updated = json_set('{"a":[{"b":1},{"b":2}]}', '$.a[*].b', 3) | head 1 | fields updated 
    fetched rows / total rows = 1/1
    +-------------------------+
    | updated                 |
    +-------------------------+
    | {"a":[{"b":3},{"b":3}]} |
    +-------------------------+

What alternatives have you considered?

N/A

Do you have any additional context?