Fix: Create QEMU VMs directly in a configured Pool

[mpywell]

• Reintroduced Pool for maptoAPI (required for creating a VM within a Pool)
• Removed step to add to Pool after creating of a VM (errors 500 already a member of pool when Pool added to maptoAPI)
• Added tests for maptoAPI for Pool

Closes #366

[Tinyblargon]

@mpywell didn't know setting the pool during create would create it in the pool, expected it to be something with the url. That probably how this bug slipped in to begin with.

The createUpdate in the test is for when the create and update tests would be the same, a create and an update test is created from createUpdate

Not sure if the pool property may be set in the api when updating the vm.
Probably better to only add it during creation and omit it during update.

[mpywell]

@Tinyblargon apologies after testing Update I found the /config endpoint doesn't support the Pool attribute, so I've moved it back out of maptoAPI. It's now set when creating a VM just before calling client.CreateQemuVm, which achieves the same result without breaking updates to VMs