Super Charging Persistence

[stormmore]

This MR is based on the my experience of running Aqua scanners in an OpenShift environment. This is back porting the fixes we have implemented in our clusters including production clusters.

Issues addressed

OpenShift security context doesn't allow for PVC for Aqua Scanner.

Due to having a separate PVC associated with the Statefulset with a fixed name, the current charts limits to only one scanner with persistence if your storage is only capable of ReadWriteOnce.

It isn't possible to add volumes and mount points potentially necessary for other tools to cooperate for the scanners.

Solutions

For the first problem, adding persistentVolumeClaim to the SecurityContextConstraints.

For the last problem, 2 additional variables have been created and mapped appropriately to both volumes and volumeMounts, called additionalVolumes and addtionalVolumeMounts respectively, e.g. #691

For the main problem, reverted change that resulted in the removal of the volumeMountTemplate in the case where accessMode is ReadWriteOnce and replicaCount is greater than 1. Using volumeMountTemplate in this way creates a unique pvc per scanner, getting around the limitation of storage that can only have one pod at a time have write access.

[CLAassistant]

All committers have signed the CLA.