Add patch-workflow helper script

[Lemmons]

This script helps with generating patches, particularly when there are multiple layers of patches which touch the same file.

I made this while working on the rfid ui, and thought it might be helpful to others, though I think it probably should be consolidated with the save-patch script, but I wanted to get feedback on if and how this should be done

[paxx12]

@Lemmons Do we re-invent the https://linux.die.net/man/1/quilt? :)

[Lemmons]

@Lemmons Do we re-invent the https://linux.die.net/man/1/quilt? :)
Omg. 🤣 I'm not particularly familiar with patching workflows. I figured there was something which should do this, considering how prevalent it is in many codebases which have dependencies which need some smallish changes, but I searched and searched for tools to help, and didn't come up with anything. 😅 I think the key here would be just to update the development instructions to indicate this is how to create/update patches.