Curriculum: add new exercise resistor-colors (round 2)

[SleeplessByte]

• add new exercise resistor-colors (Also known as Resistor Color II, follow-up for Curriculum: replace leap with resistor-color (round 2) #640)
• as an experiment 🔬 add this as core right after resistor-color

After a while, check the metrics and see if we should:

• keep resistor-colors as core
• keep resistor-color as core
• keep both as core