Prevent systemd launching service when virtualized

[smopucilowski]

I sometimes boot my linux environment within a virtualisation container, as it lives on an external SSD.

When virtualised, the intel-undervolt service fails --- it doesn't make sense to run the service when virtualised anyway.

This pull adds a condition check to the systemd service files checking if running in a virtualised or container environment.

[smopucilowski]

Bump.