graphical checker and autocompletion for python functions or classes

[jrobinAV]

• Implement a graphical autocompletion/checker for config fields representing a python object (function, class)
• Define a way to describe it in the config.schema.json

[FredLL-Avaiga]

property in json schema validation should be identified by

• "taipy_function": true
• "taipy_class": true