[Feature request] Add support for more formats and sizes of disks for mounting

[jlcvp]

I would like to run old programs I have archived here, and the mount feature is too limited. It doesn't support the .json5 format made by their own tool and only ingests .img files with very specific sizes. It would be great to have a cd-rom mount option that support disk images other than stick to the floppy disks sizes, as well as accept other image formats, like .dmg, .iso or even .zip files.

[jeffpar]

This is worthwhile, but I'm not sure when I'll have time to address all those features. However, I did just enable support for mounting local pcjs-generated .json diskette and hard disk images (no CD-ROM images), so... baby steps.