Include unicode formatting support for JSON escapes

[mikee47]

This PR improves on #2875 for JSON string formatting, updating the escapeControls function to handle unicode escaping correctly.

The check for valid UTF8 has been removed. That's erroneous and got in there because of my lack of understanding about how JSON is encoded. It's fundamentally UNICODE, so characters outside of standard ASCII must all be encoded using \uNNNN escapes. That ensures output is always valid JSON, even if string input is garbage.

The escapeControls function has a options parameter which makes it a lot more useful for various escaping requirements. This is also more efficient as the input string requires only two passes for both escaping and quoting: the first pass establishes the new string length, the buffer is re-allocated then the modified string produced.

[what-the-diff]

PR Summary

• Introduction of a New Parameter unicode in Certain Functions
  A new parameter named 'unicode' has been added to some specific functions in Formatter.cpp and Formatter.h.

• Improved escape Function in Json.cpp
  The Json::escape function in Json.cpp has been enhanced. Now it uses the escapeControls function together with the unicode parameter set to true. This allows better control and manipulation of unicode characters in JSON formatting to ensure correct and clean data interchange.