Add new meta system configuration variables

Many part of the mariadb architecture would benefit to know what type of storage is used

system_disk_type =[SPINNING | SSD | NVME | NETWORK]
system_disk_io_capacity
system_disk_latency

Such variables can be used to deprecate or facilitate dynamic config of many
InnoDB and MyRock variables

innodb_write_io_threads = auto set
innodb_io_capacity = auto set
innodb_io_capacity_max = auto set
innodb_flush_neighbors = auto set

but also inside the optimizer to compute better ordered scan computation sorting for clustered range.