Incorrect status message for LXD VM machine

[Andrew Liaw]

Low priority.

The juju machine status message uses the word "container", when a LXD VM is created.
This might confuse the user as the machine is a VM and not a container.

Some sample message:
message: Creating container
message: Container started

- Which juju version this bug was seen in (e.g. 2.9.22)?
3.1.6 controller
3.1.7 client
- What cloud the bug was seen on (e.g aws, microk8s, lxd etc.)?
local LXD cloud.

- What are the reproduction steps if you are able to be reproduce?

Deploy a machine charm on a LXD controller with the virt-type constraint to virtual-machine:
`juju deploy --constraints="virt-type=virtual-machine" tiny-bash`

Use `juju show-machine <machine_id>` or `juju status` to see the status message.
Some sample message with `juju show-machine`:
```
    machine-status:
      current: allocating
      message: Creating container
      since: 16 Jan 2024 12:18:25+08:00
```
```
    machine-status:
      current: running
      message: Container started
      since: 16 Jan 2024 12:18:28+08:00
```

Optional: Using `lxc list` should confrim the this is a virtual machine instance and not a container:
```
| juju-3106ff-57 | RUNNING | 10.176.39.106 (enp5s0) | | VIRTUAL-MACHINE | 0 |
```

[Joseph Phillips (manadart)]

This should be simple. At the time these statuses are emitted, I believe we will have the type on hand.

Incidentally, we might as well change the messages for KVM brokerage at the same time.

$ ag 'Creating container'
provider/lxd/environ_broker.go
138: _ = statusCallback(status.Allocating, "Creating container", nil)

container/lxd/manager.go
123: _ = callback(status.Provisioning, "Creating container spec", nil)
126: _ = callback(status.ProvisioningError, fmt.Sprintf("Creating container spec: %v", err), nil)
130: _ = callback(status.Provisioning, "Creating container", nil)
133: _ = callback(status.ProvisioningError, fmt.Sprintf("Creating container: %v", err), nil)

container/kvm/kvm.go
168: _ = callback(status.ProvisioningError, fmt.Sprintf("Creating container: %v", err), nil)
239: _ = callback(status.Provisioning, "Creating container; it might take some time", nil)

$ ag 'Container started'
provider/lxd/environ_broker.go
143: _ = statusCallback(status.Running, "Container started", nil)

container/lxd/manager.go
136: _ = callback(status.Running, "Container started", nil)

container/kvm/kvm.go
257: _ = callback(status.Running, "Container started", nil)