Follow up for !673 (merged), to make actual use of
./examples/python/gi/ovs-external-ids.py also support Reapply (akin to
nmcli device modify)
implement setting the external-ids
reapply is also supported. It will not remove external-ids that are added by somebody else.
initially I intended a different solution. Hence the commits that replace GArray with a CList (for calls) and to add a GCancellable. In the end, that code wasn't used, but as I already did it, I still submit it here. I think these changes are overall favorable, and would be useful in the future. After all, async operations naturally also need a way to be cancelled.
nmcli support is not planned for now. That is more work, which is why I added the examples script instead. Use that for testing.