Since the chacha20poly1305 constructions were the IETF variants,
we renamed those so they follow the official library better. While
here, we also fixed the argument order of the files.
The order of parameters were in the wrong order. Make them equal
to the official order of libsodium.
While here, rename NONCEBYTES to NPUBBYTES so it reflects the
underlying names as well.
If we, for some reason, fail to the error-path, then binaries allocated
are not being released properly back to the erlang runtime. Fix this
in the usual fashion by using a stack of undo-operations, and thread
them via goto.
