Add osxphotos fix --edited-image-type

[RhetTbull]

Not entirely sure I want to go down the rabbit hole of having osxphotos modify anything in Photos but this would likely be a simple feature with low probability of breaking anything.

In response to Issue #322 there are likely other apps that store non-jpeg images as a .jpeg file when editing a photo in external app. Could add a "fix" command to osxphotos that would at first have only one option: --edited-image-type

1. Find all files with adjustments that are not missing (must be present on disk)
2. check PhotoInfo.uti and check type of image (using filetype). If uti is jpeg and types don't match, use ImageConverter to convert image to jpeg and replace the copy in the Photos library (Photos expects all external edits to be type jpeg but double-check that's the expected UTI)

Support --dry-run to see what would be fixed

osxphotos fix --edited-image-type --dry-run