Allow for creation of additional load balancer for internal traffic

[bfournie]

/kind feature

Describe the solution you'd like
Currently CAPG creates a External Proxy Load Balancer to load balance traffic to a public IP address. When using CAPI to bootstrap nodes it's necessary to have a second Load Balancer for internal traffic. This request is to add the ability to create a Internal Passthrough Load Balancer.

Anything else you would like to add:
The type of load balancers to be created should be specified so that various combinations can be created, i.e. both External and Internal Load Balancers, External only, or Internal only. By default, the External Proxy Load Balancer should only be created as is currently implemented.