Write a program that prints out different greeting strings based on the time of day from Python time module:

From $00$:$00-11$:$59$ prints "Good Morning!"

From $12$:$00-16$:$59$ prints "Good Afternoon!"

From $17$:$00-19$:$59$ prints "Good Evening!"

From $20$:$00-23$:$59$ prints "Good Night!"

The program must also allow for manual entry of time to test the functionality.