Revisit default cluster wide settings

[chaudum]

There are a few cluster wide CrateDB settings that could be tweaked to provide a better default experience.

Documentation: https://crate.io/docs/crate/reference/en/4.3/config/cluster.html

Settings that could provide a different values that their defaults:

indices.recovery.max_bytes_per_sec
indices.recovery.max_concurrent_file_chunks
cluster.routing.allocation.node_concurrent_recoveries
cluster.routing.allocation.node_initial_primaries_recoveries
cluster.routing.allocation.cluster_concurrent_rebalance