load_balancer module needs to be refactored

[vchrisb]

PAS 2.5 does have the requirement for a second ingress https proxy to enable service mesh.

The load_balancer module does allow to create multiple regional load balancer but only one global load balancer, because the names in global.tf are hardcoded to e.g. ${var.env_name}-httpslb instead of ${var.env_name}-${var.lb_name}.
Also is the usage fo count misleading for type global lb, Isolation_segment is not using the load_balancer module, tcprouter can't be made optional.

I'll look into this and try do a PR.