Rework main menu to be easier for maintaining

[pecataToshev]

Currently all of the code that prints the menu is hard to follow. There is a dict with the number to function, but some of them are hidden in a sub-menu. This is hard for maintaining and you need to change multiple things to get one more option.

This being said, I've reworked the menu to:

1. Not use recursion. It was hard to follow and was checking only once for updates - on application start. This logic remains the same.
2. Allow nested menues to be easier to read and maintain. In the proposed implementation the each menu item is represented as an list. The first argument is the title to display to the user, and the second one - either a function or an array of menu items. This way we represend the submenu.
3. Added refresh function to allow only refreshing the process table without executing a function