Previously, e.g. for ORS it was:

    enb                 index=0
    gnb                 index=1
    core-network        index=2
    core-network-slave  index=3

which resulted in the following appearance order on SlapOS Master UI:

    gnb
    core-network
    core-network-slave
    enb

Note that enb comes last instead of being first as originally intended.

That happens because SlapOS Master treats index=0 as being unset and puts all
items with unset index in the end.

-> Fix this by starting explicitly-set indices from 1.

Now, for ORS, the order on UI is

    enb
    gnb
    core-network
    core-network-slave