feat(sdk): Add content delivery layer buffer configurations

[juslesan]

Background

There are two different buffers related to this PR. The propagation buffer and connection buffers. The propagation buffer is used when a node is broadcasting data but does not have neighbors to send the data to. The connection buffer is used when a new connection is formed in the network.

Summary

We can now configure these two options for the content delivery layer:

• streamPartitionMaxPropagationBufferSize can be used to set the size of the propagation buffer.
• contentDeliveryBufferWhileConnecting can be used to stop buffering while a connection is being formed.

Related changes

• renamed doNotBufferWhileConnecting to bufferWhileConnecting in the trackerless-network and dht packages.

Example use case

In a case where a publisher joins the network before subscribers the publisher stores the data to a buffer as it cannot send it to anyone. When a subscriber joins the content of the buffer is sent to the subscriber first and after that the real-time data is sent. If we don't want that the buffer content is sent then we can use set streamPartitionMaxBufferSize to 0 to avoid propagation buffering.

Additionally if the opening of connections takes long it is possible to disable buffering on connecting connections to avoid sending of old messages by setting the contentDeliveryBufferWhileConnecting as false.