Refactoring PyQT5 OldProgramer’s code for Complete CRUD App on PostgreSQL 13.2 (Fedora 34 Server)

That is an immediate follow up for post Setup PostgreSQL 13.2 and PyQT5 to run CRUD App in PyCharm 2021.1.1 on F34. Method updating table students has been added to original code and front-end window has been updated as well to have one more button to invoke “Update table” on the fly