Add xhyve component for macOS

[dgolovin]

Xhyve Hypervisor component appears among other components available for installation only on macOS. Installer behind component does not support installation, but can detect if xhyve hypervisor installed and can be used with CDK. The detection is based on docker-machine-xhive-driver availability in $PATH and cannot detect actual xhyve version. If detected Xhyve Hypervisor is used for CDK without ability to opt in for Virtualbox. All of these defines components card design and behavior:

1. Component card has disabled check box, because installation is not supported (see image below).

2. Detected/not detected state is present by dashed/solid border around component (see images below).

Xhyve is not detected.

Xhyve detected.

3. Component does not show version (see image above for point 1), because it cannot be installed and detection cannot find out version for installed docker-machine-xhive-driver.
4. There is a link below component card (see image above for point 1) that directs you to installation instructions. After you followed installation steps you can return to installer window, after detection is re-run you should see Xhyve Hypervisor card changed its state to detected. If you then switch back to terminal windows and remove xhyve then switching back to installer window will get you back where you started.
5. Xhyve Hypervisor card takes priority over Virtualbox one. It means when Xhyve is detected you cannot install or select Virtualbox to use with CDK when detected. That is implemented this way to match installer behavior on Windows where native Hyper-v takes priority over Virtualbox , because it cannot work on windows with Hyper-v enabled.

Xhyve is not installed and Virtualbox is detected.

Xhyve is not installed and Virtualbox is detected. Latter is automatically selected for install and used to configure CDK.

Xhyve is detected and Virtualbox is not present anymore no matter detected or not.