Zathras installer should record dependency versions in a separate file

[grdumas]

The problem

The installation script should create a separate file listing the names and version numbers of the installed packages and dependencies. This would be helpful for troubleshooting and improve reproducibility when performing future installations.

Desired Behaviour

After the installation is finished a log file should be created that lists the packages/dependency names and versions.

Current Behaviour

Currently the installer outputs package/dependency name and version numbers to terminal but does not create a log file.