iPhoto Support added in v0.64.0

[RhetTbull]

With v0.64.0, osxphotos now supports querying and exporting from iPhoto libraries. I hadn't planned on spending time on this but I had an old iPhoto library I wanted to bring into Photos and discovered that on Ventura, Photos will no longer open a legacy iPhoto library. The support for iPhoto is not as thorough as for Photos but all metadata including iPhoto Events and event comments are accessible vis osxphotos.

A few caveats:

1. iPhoto support is only supported on Python 3.10 or later as I had to use some type hint inspection techniques that don't work on 3.9. (If any is interested I can explain why I did this)
2. iPhoto Events are available programmatically through a new event_info property. For convenience iPhoto events are also treated as moments which are a Photos only feature. The two things are not identical but they are close and this allows you to use {moment} template field with an iPhoto library and have osxphotos "just work".
3. Missing files cannot be downloaded as iPhoto no longer works with iCloud.

Thanks to @jensb whose iphoto2xmp made this work go much more quickly as I didn't have to reverse engineer the iPhoto databases.