feat: Adding car phrases for four wheel steering modes

[jakezilla]

Four wheel steering is a popular option for rock crawlers. With a steering servo on the front and rear of the vehicle, you can have 4 different options for steering modes (sometimes called different names). I cover this setup in a video if you are curious on the application of it:
https://www.youtube.com/watch?v=qEAxVIe_x5I

My request is to add the following phrases/suggested file names:
str-f.wav - "Front Steer"
str-r.wav - "Rear Steer"
str-4w.wav - "Four Wheel Steer"
str-mr.wav - "Mirror Steer"
str-cr.wav - "Crab Steer"