[autofit] Add adjustment database. * src/autofit/afadjust.c, src/autofit/afadjust.h: New files. * include/freetype/internal/fttrace.h: Add 'afadjust' component. * src/autofit/autofit.c: Include `afadjust.c`. * src/autofit/rules.mk (AUTOF_DRV_SRC): Add `afadjust.c`.