Make an installer for Mac OSX

[NicoKiaru]

This means using:
[] using pyimagej not in interactive mode
[] write bash scripts for conda constructor

Avoiding pyimagej interactive is the crucial part. Directions given by Curtis:

https://github.com/imagej/pyimagej/commit/34ca3e67837013379d9f123d6fbf9571a8ee10a6
https://github.com/imagej/napari-imagej/commit/b6ec9c69ae1fed1dabe2b1a6df6514bf2bfc2008?w=1

Is how I did it for napari-imagej. But I think this won't work for your use case because your code needs to continue on the main thread, no? So then we are looking at another option, which I haven't coded yet: pass the rest of your code to a new callback function that PyImageJ calls after doing ij.ui().showUI() in GUI mode.