Improve ChipCounter sdram

[Christian-B]

The ChipCounter added by #436

Has a hard coded sdram and n_cores_per_chip

This appears to have a tolerance for monitor sizes but there is no automated links.

Also no adjustment for the Ethernet chips

Not a blocker for #436
but should be looked at.

[rowleya]

Potential idea: have a machine version n_scamp_cores and n_system_cores, and a machine version total cores, then when a new chip is added, remove the number of scamp cores and system cores from the total number of cores. Additionally have a machine version n_chips_per_board and n_system_cores_per_ethernet, then every n_chips_per_board also remove n_system_cores_per_ethernet.

[Christian-B]

The number of system cores comes from cfg

ConfigHandler should be extended to

1. Count the system cores
2. Conisider version while counting