Control filtering capabilities in prototypes

[half a cat]

Since the Factorio blog has presented new filtering features, I'm requesting prototype flags so mods can put the features in advanced inserters and belts only. This would be similar to how vanilla factorio only allows filtering in a more advanced type of inserter.

* Enable item filtering in splitters with a flag in the prototype. Alternatively, do like the inserter prototype and set the maximum number of filters in the prototype (which can be zero to disable filtering).
* Enable quality filtering in splitters and inserters with a separate flag in the prototype.