feat: Catchup vs follow

[tac0turtle]

In ev-node once we integrate directly with celestia-node then we should separate catchup from follow. This means that we should use the subscribe API on celestia node. When we notice that there is a new blob at a higher height then we have in our store, then we start catchup, go from local da height to highest da height. This would be the same with p2p, except that with the event driven approach we are treating catchup and follow as the same.

blocked by #2796