[Docker] Do not generate a secret key on startup

This would require www-data to be able to write the secret key now.
That would not be an issue in general, but requires awkward changes
with no real use. Users are supposed to configure a secret key
themselves.

docker-startup.sh

@@ -52,17 +52,6 @@ prepare_database() {
 	aleksis-admin createinitialrevisions
 }
 
-if [ -z "$ALEKSIS_secret_key" ]; then
-	# Use a random session secret key if none was provided
-	# In K8s, should be provided from a K8s secret
-	if [ ! -e /var/lib/aleksis/secret_key ]; then
-		touch /var/lib/aleksis/secret_key
-		chmod 600 /var/lib/aleksis/secret_key
-		LC_ALL=C tr -dc 'A-Za-z0-9!"#$%&'\''()*+,-./:;<=>?@[\]^_`{|}~' </dev/urandom | head -c 64 >/var/lib/aleksis/secret_key
-	fi
-	ALEKSIS_secret_key=$(cat /var/lib/aleksis/secret_key)
-fi
-
 # Wait for database to be reachable under all conditions
 wait_database