[FR] Add meatpack serial packing support

[ellensp]

This is a feature request.

Meatpack is a gcode serial stream packing algorithm. It combines common pairs of characters into one byte for transmission.

Needs to be in the client and firmware.

Has been added to Marlin https://github.com/MarlinFirmware/Marlin/pull/20802 and is being added to Prusa-Firmware https://github.com/prusa3d/Prusa-Firmware/pull/2955 There is a octoprint plugin for this is https://github.com/scottmudge/OctoPrint-MeatPack The octoprint plugin is in python, so should be easy to implement in Printrun