EL9: Adding parsing NM resolv.conf for dns entries

[Obihoernchen]

trafficstars

Adding parsing NM resolv.conf for dns entries (if there is no lease file).

EL9 does not have /var/lib/dhclient/*$str_inst_nic* anymore. Data is in /var/run/NetworkManager/resolv.conf now.

Try to get DNS config from this new file.

[Obihoernchen]

Might fix https://github.com/xcat2/xcat-core/issues/7407

[samveen]

Might fix #7440

This is this PR itself. I expect you wanted this to be some other bug.