Allocation of CIDRs for subsystems on the real network

Not linking to INSTRM-70, since this is a task for real allocation of resource.
We need to have definition and/or registration of allocation of subnets for subsystems at somewhere, as well as DHCP definitions in dnsmasq. So, we need to agree in this ticket on:

• where (repository) and how (description file format) we will register allocations
• registration management - will not change so much (it's subnet but not address)?
• basic idea of allocation

Requirements (or desires?) of allocation criteria should be:

• pack related subsystem in close subnet (e.g. xCU follows ENU), and in organized order (e.g. SM2 follows SM1)
• allocate by one CIDR (to make thing simple) as much as possible, with slack in each subsystem
• first address (.164.1) will be taken by default gateway (port at Subaru core switch), so we'd better to assign first CIDR to network switch subsystem