Use ConfigEntry for hardcoded configs for memory and storage categories

Some of following memory and storage related configs are still hardcoded, We try to use ConfigEntry and put them in the config package :
spark.storage.cleanupFilesAfterExecutorExit
spark.diskStore.subDirectories
spark.block.failures.beforeLocationRefresh
spark.storage.unrollMemoryThreshold
spark.storage.memoryMapThreshold
spark.memory.storageFraction
spark.memory.offHeap.enabled
spark.memory.offHeap.size