add 'resolv_conf_dangling_symlink' test

Created by: fpokryvk

Add check, that if resolv.conf is dangling symlink, it will be followed and new file will be created, when main.rc-manager=file in config

Add new steps: "{filename}" is file "{filename}" is symlink "{filename}" is symlink with destination "{destination}" Remove file "{filename}" if exists Remove symlink "{filename}" if exists Create symlink {source} with destination {destination}

@Build:nm-1-12