Add tutorial: "Prepare production-ready environment", with everything charmed

Using ck8s 1.32 charm + [`virt-type=virtual-machine`](https://documentation.ubuntu.com/canonical-kubernetes/latest/charm/howto/install/install-lxd/) + [ceph-csi](https://documentation.ubuntu.com/canonical-kubernetes/latest/charm/howto/ceph-csi/).

Potential starting point:

```bash
sudo snap install juju --channel=3.6/stable
sudo sysctl -w fs.inotify.max_user_instances=1024
sudo sysctl -w fs.inotify.max_user_watches=1048576

# Disable IPv6
echo "net.ipv6.conf.all.disable_ipv6=1" | sudo tee -a /etc/sysctl.conf
echo "net.ipv6.conf.default.disable_ipv6=1" | sudo tee -a /etc/sysctl.conf
echo "net.ipv6.conf.lo.disable_ipv6=1" | sudo tee -a /etc/sysctl.conf
sudo sysctl -p

lxd init --auto
juju bootstrap lxd
juju add-model ck8s

# https://documentation.ubuntu.com/canonical-kubernetes/latest/charm/howto/install/install-lxd/
juju deploy k8s --channel=1.33/beta --revision=1024 --constraints='cores=8 mem=16G root-disk=40G virt-type=virtual-machine'

# https://documentation.ubuntu.com/canonical-kubernetes/latest/charm/howto/ceph-csi/
juju deploy -n 1 ceph-mon \
--constraints "cores=2 mem=4G root-disk=16G" \
--config monitor-count=1 \
--config expected-osd-count=1

juju deploy -n 1 ceph-osd \
--constraints "cores=2 mem=4G root-disk=16G virt-type=virtual-machine" \
--storage osd-devices=1G,1 --storage osd-journals=1G,1

juju integrate ceph-osd:mon ceph-mon:osd

CEPH_NS=ceph-ns # kubernetes namespace for the ceph driver
juju deploy ceph-csi \
--config provisioner-replicas=1 \
--config namespace="${CEPH_NS}" \
--config create-namespace=true
juju integrate ceph-csi k8s:ceph-k8s-info
juju integrate ceph-csi ceph-mon:client
```