Logging: JSONFormatter

[obiltschnig]

Add a JSONFormatter class to the Foundation logging framework.
This formatter should generate JSON-formatted logs, with one JSON document per log message.

Example for JSON schema:

{
    "timestamp": "2024-09-26T13:41:23.324461Z",
    "source": "sample",
    "level": "information",
    "message": "This is a test message.",
    "thread": 12,
    "file": "source.cpp",
    "line": 456,
    "params": {
        "prop1": "value1"
    }
}