EXIF DateTimeOriginal: Properly handle "0000:00:00 00:00:00" about metadata-extractor

[StefanOltmann]

@drewnoakes

To improve my code, I've updated it to check whether the date string includes any of the available placeholder patterns.

As for fixing the library, I recommend invoking setLenient(false) and returning null if a parsing error occurs. This approach should handle all scenarios.

/**
 * A collection of possible placeholder values that older cameras
 * may have written for exif:DateTimeOriginal.
 * So far, we have seen actual photos with the value "0000:00:00 00:00:00"
 * The other entries are assumptions based on common patterns.
 */
val placeHolderDateStrings: Set<String> = setOf(
    "0000:00:00 00:00:00",
    "0000:00:00 00:00",
    "0000-00-00 00:00:00",
    "0000-00-00 00:00",
    "0000.00.00 00:00:00",
    "0000.00.00 00:00",
    "0000-00-00'0'00:00:00",
    "0000-00-00'0'00:00",
    "0000-00-00",
    "0000-00",
    "00000000",
    "0000"
)

fun isDateStringPlaceholder(dateTimeOriginal: String?): Boolean =
    dateTimeOriginal == null || placeHolderDateStrings.contains(dateTimeOriginal)