pager: Also set SMK in LESS, fix LV=C to be LV=-c
Sync the LESS environment with systemd to make it more user-friendly than just a blinking colon:
- S disables the terminal bell
- M makes the output verbose, so the prompt is not ":" but "lines 1-n"
- K means that Ctrl+c exits the command
Also fix the LV= environment variable to use -c and not C.