Add support for memory autoscaling

[Elyytscha]

Feature Request

Is your feature request related to a problem?

actually you can't autoscale based on memory, so you can't avoid OOMKills due to temporary high user workload resulting in high memory utilization

Describe the solution you'd like

Add support for memory autoscaling, in actual state only CPU based scaling is supported.

autoscaling.targetCPUUtilizationPercentage: 100 # Target average Memory utilization (represented as a percentage of requested Memory) over all the pods.