Support installing multiple Samba packages

Summary:
Some distros (such as Manjaro) require multiple packages to be installed before a working
Samba stack is present. This patch adjusts the CMake packaging and Samba auto-
installation feature to support passing a comma-separated list of packages to support
such distos.

Test Plan:

• Remove samba and try auto-installation again; it still works
• Invoke CMake with multiple packages (e.g. samba,rename) and try auto-installation again; both packages and their dependencies get installed

Reviewers: apol, Frameworks

Reviewed By: apol

Subscribers: bruns

Differential Revision: https://phabricator.kde.org/D21327