Converts a day and time to a schedule array index.
Day of week (0=Monday, 6=Sunday).
Hour of day (0-23).
Minute (0-59, will be rounded to nearest 30).
// Monday 08:00timeToIndex(0, 8, 0); // Returns 16 Copy
// Monday 08:00timeToIndex(0, 8, 0); // Returns 16
// Wednesday 14:30timeToIndex(2, 14, 30); // Returns 125 Copy
// Wednesday 14:30timeToIndex(2, 14, 30); // Returns 125
Converts a day and time to a schedule array index.