I think this could just be on the browser/client side. There could be a browse button to the left of import. The browse could just pop up a file system window and let you pick a file. the import would still tell the the browser to fetch the file.
I am just finishing up testing on a VSCode extension that I wrote that allows for publishing to the Hubitat from within VSCode directly. This will allow you to edit the files locally in VSCode and will a single click publish them to Hubitat.
PM me if you want to help test it!
That being said, the real feature request should be for hubitat to codify the publishing api to publish apps/drivers/libraries. Currently its reversed engineered from the web interface