We can now explicitly set any property on a given pool by using the new
Property field in the CephBlockPool Spec.
Also, this fixes the case where both `CephBlockPool` and `CephCluster`
are created at the same time. When Rook creates the pool, the cluster is
still being bootstrapped and the global option
`osd_pool_default_pg_autoscale_mode` has not bee set yet. So the pool
gets created but its `pg_autoscale_mode` property is set to `warn`
instead of `on`.
Closes: https://github.com/rook/rook/issues/5608V
Signed-off-by: Sébastien Han <seb@redhat.com>