Toggle for custom CO-RE BPF

[erthalion]

It's necessary to make custom CO-RE BPF flexible enough to be able to switch
between vanilla & custom implementation:

• This could be useful as a workaround if something doesn't work
• It will allow cross-verifying results between two collection methods

Such toggle has to be implemented internally, and not visible to users. The
proposal is an environment variable, which could be updated manually if needed.
The tricky part here is how it should be represented in the stackrox. Ideally
it should be Collector only thing, but since we plan to manually change it, we
have to deal with installations using rhacs operator -- and without knowing
about the toggle the operator will erase it with at the next sync.

Figure out if it's possible to handle the operator use case, or otherwise
introduce a regular option (as with the collectionMethod, which is visible
everywhere), but do not expose it in the UI.

Part of #1320