* draft of model tracer visualiser
* add context manager in addition to decorator
* add debug utils to init
* move model debugging utils to dedicated file
* add documentation
* protect some imports
* format
* move and protect imports
* format
* doc: improve errors in case of broken dummy imports.
* format
* use automatic torch backend
* update doc
* fix backend
* (TEMP) move to dummies while backend wait
* update documentation
* doc
