Reading exif metadata from Images [Image Import]

[benjaminwinger]

The image import module, as well as loading frames from the disk and from video devices, also needs to fill the frame's metadata object with information from the telemetry file. This is facilitated by the use of exif metadata from the pictures.
(this is already discussed in more detail in the issue describing the ImageImport module however this issue is specifcally for the exif metadata)

We need someone to create a helper function that will read the timestamp from an image file using exiv2.
Exiv2 will also need to be added as a dependency to the project.