K8s resource limits

It's a common good practice to define resource limits for k8s resources. 

The basis for limit numbers can be scalability test results for 2 OLTs, 16 PON ports per OLT and 32 Subscribers per PON with 10 Voltha stacks. 

The proposed formula for resource limits is:

For the  Requests limit type:

max value of memory and cpu usage in mebibytes/milliCPU

For the Limits limit type:

Request limit  for memory and cpu usage * 2 (in mebibytes and milliCPU)