Put Falco pods under VPA

[lsroe]

What this PR does / why we need it:

Falco pods need to be able to dynamically increase memory for very large nodes as two ringbuffers need to be created for each CPU

Which issue(s) this PR fixes:
Fixes #348

Special notes for your reviewer:

Release note:

Falco pod memory handled by VPA

[marwinski]

I am reluctant to allow VPA control here. We currently have a memory leak in Falco which sometimes lead to OOM kills, but the current limits are good also for large machines, just not for very large machines with lots of cores. Putting Falco under VPA control would mean that we allow the leak to consume more before being OOM killed.

From my point of view a better approach would be to configure more memory for machines with a high number of cores. The ways to do that are debatable and I don't have a really good idea just yet.

[gardener-robot]

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