ncm-metaconfig: support daemons with actions

As discussed with `ncm-ceph`, do not modify `self`.

I see two options, and they probably don't need separated functions:

```perl
my %actions;
...
$actions{$action}->{$daemon} = 1;
```

Or, if we only want one action per daemon:

```perl
my %actions;
...
$actions{$daemon} = $action;
# or, if you want the first processed action to win
$actions{$daemon} ||= $action;
```