WIP: [th/libnm-properties-override]
Refactor libnm's handling for the property meta-data.
Move the common parts of NMSettInfoProperty
to a NMSettInfoPropertType
. This saves some 13K at runtime. Also, it makes more sense to split the property-info in per-property information (e.g. the "name") and the property-type (with the function pointers for the behaviour).