Weather Toolkit: Clip data extent prior to processing

**Describe the task**

The four panel chart plotter code currently uses the entire global/regional grib file. We could apply a mask to the data based on the latitude and longitude plus a buffer to restrict the quantity of data being processed. The latitude buffer can be pretty tight, but the longitude buffer needs to be quite wide to account for the spatial reference used by the four panel charts.

Clip data extent prior to processing 4-panel weather charts instead of using the entire global extent.

**Acceptance Criteria**
- [ ] Apply latitude and longitude extent mask to RDPS and GDPS model data prior to processing charts.

**Additional context**
- Currently reading in data for all latitudes and longitudes.
- Or here

Locate the four-panel chart plotter and the RDPS/GDPS model-data processing paths, then inspect how latitude, longitude, and chart spatial references are handled. Done means both model datasets are masked with suitable buffered extents before chart processing, while preserving the four-panel chart coverage.

Written by the indexing model from the issue text.