install.sh: apply sysctl.d files on non-packaging installation

We don't apply sysctl.d files on non-packaging installation, apply them
just like rpm/deb taking care of that.

Fixes scylladb#7702

Closes scylladb#7705

(cherry picked from commit 5f81f97)

install.sh

@@ -342,5 +342,9 @@ elif ! $packaging; then
     mv /tmp/scylla.yaml /etc/scylla/scylla.yaml
 
 
+    for file in dist/common/sysctl.d/*.conf; do
+        bn=$(basename "$file")
+        sysctl -p "$rusr"/lib/sysctl.d/"$bn"
+    done
     $rprefix/scripts/scylla_post_install.sh
 fi