Simplify VER_METHOD in PointStat and EnsembleStat (point)

`VER_METHOD` is likely to be redundant, this issue is to explore if it can be removed.

The separation of both methods is inherited for the VER system. With VER, there were two verification strategies:

- Station Based Verification: Matches forecast-observations pairs on station, and validity time, storing the pairs and using VerPy to calculate and plot the statistics. Allows masking by lists of stations.
- Area Based Verification: Selects the observations on area masks and calculates the statistics for those areas, with VerPy used for plotting.

With METPlus, the method is implicit in the output type. It is likely, then, that `VER_METHOD` is not needed. This issue is to explore whether that is possible.

Start by tracing VER_METHOD through PointStat and EnsembleStat, then compare how METPlus output types distinguish station-based and area-based verification. Determine whether the setting is redundant without changing either behavior; done means reaching and recording a clear decision about removal and identifying all affected references.

Written by the indexing model from the issue text.