Create to new directory

[martindurant]

Some "create" functions (e.g., pyscript create) want to write only to a new directory. So we should allow this with a tempdir, and cp() to the original destination.

[martindurant]

Bonus addition: some creation tools want a few standard fields to fill out, like app name, author etc. We could have a global config to provide such defaults.

[martindurant]

Another bonus: creation tools normally run locally, but we could auto-move to remote; otherwise, we had better check that the project is local before trying to invoke anything, like artefacts already do.

[martindurant]

Create to tmpdir function now exists as context manager in utils.make_and_copy, but not called from anywhere