Update _common.sh

[Thovi98]

Add libimage-exiftool-perl dependencie

Problem

• Some Photonix services crashes

Solution

• Add libimage-exiftool-perl as dependencie

  PR Status

• [x] Code finished and ready to be reviewed/tested

• [x] The fix/enhancement were manually tested (if applicable)

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[tituspijean]

I got the same issue after having Photoview, Photonix and LibrePhotos running on the same server (for testing purposes). Removing Photoview or LibrePhotos ended up removing exiftool and making Photoview fail. (Though I fixed it with a broad apt install exiftool)

[Jules-Bertholet]

Thanks for this!