dracut: add more checks and split vlan_over_everything test

Add more check using nmcli_con_prop and run all checks twice (except wait_for_ipX_renew), to make sure after renew no property is lost. Many checks support * search, when explicit value is too complex or order of values is unpredictable. nmcli_con_prop supports last optional argument - number of retries (e.g. to wait for IPX.ADDRESS). Default is 1 retry (maybe subject to change to increase stability).

Tune dhcpd options to provide rebind and renewal time options, so renewal should be quicker (for ipv6 it works fine, renewed after 10s, for ipv4 after 35s with the same configuration :( )

vlan_over_everything test split to multiple tests as libvirt throws kernel panic on some systems when 7 virtual NICs are used (and debuging such a test is a nightmare).