Exposed utility functions for SpoolFile creation

Exposes two functions newRandomPointsSpoolFile and newRandomContentsSpoolFile. These functions, given a SpoolName produce a new FilePath for points and contents respectively.

The main motivation for this change is so that collectors can rotate points and contents files independently, as they grow at different rates. This is not rotation in the MarquiseD sense (new -> cur), but from one file name to another (e.g. "XYZ123" -> "456ABC"). This is so that spool files do not reach unmanageable sizes.