Add "Cloud Builder" support to haikuporter

[kallisti5]

Haiku can be booted in several cloud environments. (Digital Ocean, AWS, Vultr)
With the cloud_init hpkg in Haikuports, the VM's can be provisioned on the fly at startup by the cloud providers above.

Example:
https://gist.github.com/kallisti5/d84de68d232a22b3d55b66f8618ceb42

In theory, haikuporter could perform Haiku package builds at any cloud provider via a few API calls followed by an SSH connection.

1. haikuporter Provision new Haiku VM via API calls
2. haikuporter SSH keys provisioned via cloud_init in booting VM.
3. haikuporter SSH's to new server
4. Builds happen
5. haikuporter gets artifacts
6. haikuporter destroys the Haiku VM via API calls.

• 1 is the most work needed, should be cloud agnostic and extendable
• 2 isn't really much work
• 3 already happens today over ssh, just needs dynamic IP fed to it from step 1
• 4 already happens today over ssh
• 5 already happens today over ssh
• 6 is similar to 1 in reverse