also moved all test in standalone files ready to be included in the
zencode documentation

finally a clear way to align documentation and actual version of
zencode contracts in a consistent way, locked also by versioning. The
same scripts in test/zencode_* are those shown on the documentation
website, collated at build and ran at every CI test.

still need an update to zencode 1.0

also enhanced documentation and added templating docs merging test
files using esh

added faster and more compact CBOR input/output format encoding from
RFC 7049 "Concise Binary Object Representation". Accidentally found a
bug in Zencode execution whose removal significantly improves
speed. Feels good :^) Also added rules for configuring format from
zencode and cleaned up a bit.

only provide _tobuf_ calls to bindings as py and go
addresses issue https://github.com/DECODEproject/zenroom-py/issues/2