Handle UTC offset in addition to local time

[JorgenMygindPilgaard]

The following tags are read/updates when when showing/correcting Date-field in the UI:

• XMP:Date=2024:05:25 17:11:45+02:00
• EXIF:DateTimeOriginal=2024:05:25 17:11:45, OffsetTimeOriginal=+02:00
• EXIF:CreateDate=2024:05:25 17:11:45, OffsetTimeDigitized =+02:00
• EXIF:ModifyDate=2024:05:25 17:11:45, OffsetTime=+02:00
• IPTC:DateCreated": {"access": "Read/Write}"},
• QuickTime:MediaCreateDate": {"access": "Read/Write"}, ....iphone stores local time here it seems, for MOV-files
• QuickTime:CreateDate=2024:05:25 15:11:45 .... Iphone store UTC-time here it seems, for MOV-files
• QuickTime:ModifyDate=2024:05:25 17:11:45 ....iphone stores local time here it seems, for MOV-files
• QuickTime:MediaModifyDate=2024:05:25 17:11:45 ....iphone stores local time here it seems, for MOV-files
• QuickTime:TrackCreateDate=2024:05:25 17:11:45 ....iphone stores local time here it seems, for MOV-files
• QuickTime:TrackModifyDate=2024:05:25 17:11:45 ....iphone stores local time here it seems, for MOV-files
• RIFF:DateTimeOriginal(Read)": {"access": "Read"},
• File:FileCreateDate(Read)=2024:05:25 17:11:45+02:00

The app assumes that the Date/Time is local date/time. several of the tags has a UTC-offset tag holding the time-offset from UTC-time. This time-offset should also be shown and editable in the UI.