Fix increasing size of backups

[eloiferrer]

Describe the bug
The size of the backup for the images keeps increasing due to the cache and temp directories.
This MaRDI4NFDI/docker-wikibase@a91261c apparently didn't work.

-rw-r--r--  1            9000            9000 3.8G Sep 20 06:48 images_2024.09.20_04.15.01.tar.gz
-rw-r--r--  1            9000            9000 4.1G Sep 21 06:45 images_2024.09.21_04.15.01.tar.gz
-rw-r--r--  1            9000            9000 4.4G Sep 22 06:51 images_2024.09.22_04.15.01.tar.gz
-rw-r--r--  1            9000            9000 4.9G Sep 23 06:55 images_2024.09.23_04.15.01.tar.gz
-rw-r--r--  1            9000            9000 5.3G Sep 24 07:00 images_2024.09.24_04.15.01.tar.gz
-rw-r--r--  1            9000            9000 5.8G Sep 25 07:03 images_2024.09.25_04.15.01.tar.gz

Expected behavior

To Reproduce

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