Convert personality txt files to yaml, replace print with log, and update app.py

[zhuo-yoyowz]

Convert personality txt files to yaml, and update app.py

[adrianboguszewski]

The extension change isn't enough for supporting yaml, because in code it still behaves as txt.
Please look at the virtual AI assistant, how yaml files are handled :)

[zhuo-yoyowz]

Thanks for the comment! Updated the yaml file, according to the virtual AI assistant demo. Please help review again. Thanks!

[adrianboguszewski]

It still won't work as expected. YAML files must be read through the yaml library. Once again, check the virtual AI assistant for loading and handling the content of the file.

[zhuo-yoyowz]

Updated codes with YAML way to load the personality file. Please help review. Thank you!