Unify all generators to use rounding function in tools/drawing_tools.py

There are some generators using a helpers.py file.

Every helpers.py file has a rounding function inside, used for courtyard calculation.

This MR make every generator to use the rounding function in tools/drawing_tools.py, and it also enhances the rounding function so:

• it doesn't crash if the number to be rounded is zero.
• handle a list of values
• truncate the output value to 6 decimals to avoid floating point rounding errors.