Add script to add practice exercise

[ErikSchierboom]

I'm planning on maybe adding a couple of exercises, and this script helps (newer tracks get this for free: https://github.com/exercism/generic-track/blob/main/bin/add-practice-exercise)

[jonmcalder]

Thanks Erik! Have only checked / scanned this quickly from my phone for now so I'll want to actually test it out later but I approve nevertheless. Is the idea to keep this generic or to (optionally) tailor it further to each track?

[ErikSchierboom]

Is the idea to keep this generic or to (optionally) tailor it further to each track?

It's a generic starting point, but each track should tweak it as they desire.

[ErikSchierboom]

I'll wait with merging until you've tested it.

[jonmcalder]

Thanks I have since run it and all looked good so I think we can merge.