Add ability to reorder Docker images

[etnguyen03]

As of writing, it appears to be impossible to reorder the list of Docker images. It'd be nice to have that functionality.

For instance, if we wanted to add, say, Ruby (for Ruby on Rails - or some other framework/language), it's impossible to then add Python 3.10 in order with the other Python images without removing the Ruby image and re-adding it, which might not be the best thing to do.