Remove/replace get_block_range
This method was made available for hivemind usage as it allowed to sync the old hivemind faster. We should remove this API or make it very limited as it is no longer used by hivemind. It is a wild API method compared to the other methods. It reads a lot of data from hived and multiple simultaneous calls can cause performance problems for the other lighter calls.
I'm in favor of removing this method as it is very easy to have a HAF version on HAfAH. The HAF version can read for example 100 blocks instead of the current 1000 blocks.