"Performing Upgrade" in case of upgrade

- Otherwise "Performing Installation"
Merge pull request #247 from kobliha/perform_upgrade

Using different dialog label in SlideShow depending on current installation method
InstallationProperties is used in all types of First Stage

- Installation, upgrade, etc.
- Systemctl is not available in inst-sys
Changes and version
Merge pull request #248 from kobliha/systemd

Using different Systemd Unit Properties (handler) in inst-sys (Stage.initial)