dev/dan/issue-73: cosmetic update of patch scripts

[danpage]

After completing an update to the Docker build, here are some ideas to tweak the patch scripts:

• retain uniform steps per component (even when a step is a NOP); this means we can alter the steps without altering what uses them (e.g., the Docker build, or instructions for use)
• include explicit steps for the pk component (vs. somewhat implicit)
• remove X-all.sh: either have one for all or no steps, otherwise it's confusing
• move to component-task.sh naming to clean up a little

[ben-marshall]

I've merged this all into my dev branch - works fine :)