Enable operator user to specify sampling strategies

[objectiser]

As described here, it is possible to specify adaptive sampling strategy details in a json file.

As changes to the sampling strategies may be automatically reloaded when changed, it may be appropriate to create this mounted file as default (albeit empty) - so an update to just this part of a CR does not need to necessarily cause the restarted.

We should consider in general what the update approach should be when changes are applied to the CR. Maybe a general rolling update approach would be safer.

[jpkrohling]

As changes to the sampling strategies may be automatically reloaded when changed, it may be appropriate to create this mounted file as default (albeit empty) - so an update to just this part of a CR does not need to necessarily cause the restarted.

+1

We should consider in general what the update approach should be when changes are applied to the CR. Maybe a general rolling update approach would be safer.

This request requires more thought and a lot of QE, to make sure we don't end up losing in-flight data to the agent and collector. Somewhat related: #42