pub-sub: Subscribe with filter

[matianxing1992]

In the pub-sub, sometimes we leave the application to decide what names should be watched (prefix match, regex match, etc.).

One general solution is to add a new function in SVSPubSub:
uint32_t SVSPubSub::subscribeWithFilter(const NameFilter& nameFilter, const SubscriptionCallback& callback, bool packets = false);

I'm now working on this feature.