BUG: Unit File generator doesnt replace default values

**Describe the bug**
Unit files generated have speciffic fields, like user, group etc. These are populated with default vaules that _should_ be replaced with _actual data_. that doesnt happen currently. 
[Code](https://github.com/HilkopterBob/PackageLock/blob/19c03aa68a61374c40fcca6f4093f96c32df79fc/main.go#L175C1-L180C1)
