Dependency addition for Yocto build

[dbouras]

This took me a while to figure out so I'd love to save anyone else the trouble.

When building the Linux Yocto distribution, getent is in the glibc-utils sub-package and is not installed by default. When it's missing there's an uncaught exception in NavWindow.js that results in all navigation buttons being unresponsive.

Please add getent to your list of dependencies when building from source.

Once again many many thanks for a truly amazing cockpit application!