Full JSON Chat API support

Several years ago, a new json-based chat text system was introduced to the game. While the old system, using a formatting character (§) and specific codes ([0-9a-f]), allowed for custom color and formatting, the new one provided extra features, such as click and hover events.

As stated in the change-logs for the most recent snapshot (20w17a), text will no longer be limited to the 16 default colors, but will now allow the use of the full RGB spectrum. While the client still parses text from the legacy system correctly, *the new color system is only available through the new one*.

Considering the above facts, a sensible suggestion at this point, would be to provide full-fledged API support to the new chat system in every game mechanic that utilizes it (Chat, Scoreboard, Books, to name a few).