Provide guidance regarding resource requests and limits

[adrienjt]

In a cluster with 120 nodes and 2600 pods, the agent pod is OOM killed before it can send any observation. Increasing the default memory limit fixes the issue, but we need to provide guidance on how much memory is needed as a function of node and pod cardinality.

[adrienjt]

v0.4.0 introduces a Helm chart, where the resource requests and limits aren't set by default, so the agent won't be OOM killed in a larger cluster. Users can (and should) set requests and limits depending on the size of their system. We still need to provide guidance.