Improve min-report to aid debuggability.
Delay run-file parsing to load_interface.

Run-file name is now interface-dependent; this is an unnoticed
regression after multi-interface improvements.
Improve debug statements and get rid of unneeded _IS_PARSING_RUNFILE variable assignment.
Extend default interface calculation for status|continuous|once|last.

For these targets, list all interfaces by default.
Fix systemd_list_interfaces: pass --full to avoid ellipsizing unit names.