LVGL Kft switches to freemium; closes lv_xml module

LVGL has begun relicensed and removed the lv_xml module from and moved it under LVGL Pro

More discussion here: https://github.com/lvgl/lvgl/issues/9663

Have to read the commit history on this one to see the order things happened - lv_xml appears to have started as MIT licensed with everything else, then license changed last fall, then it was removed with claims of always-been-proprietary.