Responsibility for package installation

[stanislavlevin]

For now, pr-ci unconditionally installs all the IPA packages:

dnf install -y /vagrant/rpms/*.rpm

This is the simplest way, yes. But it has several disadvantages, such as:

• inability to detect missing runtime dependencies on IPA packages
• the inability to provide VM cleared from IPA RPMs
• the inability to provide step-by-step IPA installation combined with RPM installation
  and so on.

The problem is that RPM(install+uninstall) != initial state.
For example, freeipa/freeipa#5376

I propose to move IPA RPMs installation responsibility to ipatests:

• place built packages(RPMs) somewhere on the filesystem on each VM
• install nothing from them by default
• install ipatests on the controller from RPMs storage at the provisioning phase
• install only required packages on the setup from RPMs storage at tests runtime

[flo-renaud]

See also freeipa #7525: [CI] Client installations are performed with server packages installed

As all the packages are installed (even the server packages on a client machine), we fail to detect packaging issues. Installing only the packages required by the machine role would definitely help.