Revert "Prison metadata is retrieved from the encrypted link or added when missing."

This reverts commit 7942d756163ae9b6de20ae9396545b54de689a88.
Revert "Prison metadata gets stored in the encrypted link (state)."

This reverts commit 09f9ad5c515213b16aaff9826d4e688aa251f317.
Remove prison structure saved in the session.