Feature request: allow keyboards with identical layouts to use the same .json layout files

[leviport]

While testing #136, I tried importing my launch_1 layout file for the launch_2, which was not allowed since they have different model names. After copying the .json layout file and changing the model on line to from launch_1 to launch_2, it imported smoothly. That got me thinking, and I tried importing my oryp6 layout onto a gaze16-3050. The same thing happened -- my layout wasn't accepted until I changed the model from oryp6 to gaze16-3050, then it imported without issue and behaved fine.

So I think it would be a nice addition if compatible layouts were cross-importable. If the layout is otherwise identical, then the model name not matching might not always be a good reason for it to refuse to import the layout.

[ids1024]

This shouldn't be too hard since the layouts were de-duplicated in #60. Though launch_1 and launch_2 currently are separate (identical) layouts because of how it's generated from the QMK source, which doesn't have the same logic for sharing this that EC has since system76/ec#205.