libknot: add yparser

Knot.files

scripts/update-parser.sh

src/Makefile.am

src/libknot/errcode.c

src/libknot/errcode.h

src/libknot/internal/yparser/yparser.c

src/libknot/internal/yparser/yparser.h

src/libknot/internal/yparser/ypbody.c

src/libknot/internal/yparser/ypbody.h

src/libknot/internal/yparser/ypbody.rl

src/libknot/internal/yparser/ypformat.c

src/libknot/internal/yparser/ypformat.h

src/libknot/internal/yparser/ypscheme.c

src/libknot/internal/yparser/ypscheme.h

src/libknot/internal/yparser/yptrafo.c

src/libknot/internal/yparser/yptrafo.h