Features:
* resolved:
- - CNAME resolver
- cache
- IDN
- DNSSEC
- LLMNR
- mDNS/DNS-SD
- - nss client module
- DNS-SD service registration from socket units
+ - port sd-resolve to direct bus calls
+ - nss module: fallback to glibc dns modules if resolved cannot be contacted
* Allow multiple ExecStart= for all Type= settings, so that we can cover rescue.service nicely