erp5 jupyter kernel: print capturing using AST processor to modify print calls
This is a duplicate of !150 (closed), because by unknown reasons it's showing problem to merge.
Before, we we're redirecting sys.stdout and this doesn't play nice with the
distribute architecture of ERP5 and our Jupyter kernel needs to be adjusted for this.
So, we're now using an AST processor to fix print calls. It will modify the print and make it write to a different file-like object. All the writes are collected after code execution and sent to Jupyter.
It's still necesasry though to fix print inside other libraries. But for this
deeper investigation is necessary because we cannot replace print as a statement
inside exec contetx, it needs to be used as a function. Code can be compiled to
run with print as a function, but then external libraries calls will be
broken.