allow running importMcDev without applyPatches (to not interrupt)

[MiniDigger]

tried it here https://github.com/PaperMC/paperweight/tree/feature/importmcdev
obviously doesn't work, because the files will not be added to git at the right spot.
maybe we wanna automate stashing and then do a fixup commit and rebase?

[DenWav]

This is likely not to be possible / too difficult due to the fact that this has to modify the base patch to add the file (which means patches have to be applied and re-built). If someone can figure out a way to do this that won't blow away changes (which would include cases where someone's in the middle of an interactive rebase and editing a commit in the middle of the history) then that would be cool.