DAL/Node: fork amplificator before starting the crawler

The amplificator process was started (after the refactoring in !14199 (merged)) after the crawler of L1 blocks, meaning that the crawler "communicated" to two processes, the main one, and the amplificator. This leads to blocks being processed with large delays. (It's unclear to me what happens in details, but this is not what was intended.)

Now we start the amplificator process sooner, just after initializing the crypto.