feat(tiering): Faster small bins serialization

[dranikpg]

[dranikpg]

@romange Please look only at the idea, I left some open questions

[romange]

I thought about this more. Master is the more fragile piece compared to slave or an instance loading the snapshot. That means we want to move the complexity to Load phase and I think it is possible to do if we just send the segment support at the end. This suggestion tracks pending items on the master side, i.e. maintains per object granularity. I think it's worth extending RDB support to maintain segment granularity (i.e. send 4K pages with their offsets.).

[dranikpg]

Closed in favour of #3396