[FEA] Implement Java/JNI function `applyNullMask`

We need a function in Java/JNI to apply a null mask onto some provided input column. This functionality is used a lot in Spark-rapids plugin.

Currently, we can achieve this using `copy_if_else` but we have to create and provide a null scalar for the `else` (if not valid) option, which is a bit inconvenient and incurs additional maintenance overhead.