Stop serializing numberOfValues and simplify the verbose data format in attribute system

In the past when we serialize items between client and server,

we serialize "NumberOfValues" info and we also serialize data for each item as(Ex. componentItem) [ { "Val": { "Resource": "uuid-1", "Component": "uuid-2" } },{"UnsetVal": True} ... ] which is pretty verbose as David has pointed out.

Actually since we serialize the values in the ComponentItem as a array, the array size would be naturally equal to the NumberOfValues. There is no need to repeat this info.

Meanwhile, it would be better to serialize the data as: [ [ "uuid-1", "uuid-2"], ... ] which is cleaner and easier.