SFMS Insights: Create cog from snow coverage

**Describe the task**
When processing snow coverage data we currently create a pmtiles file for display on the map. Creating the pmtiles layer is quite slow. We moved towards creating Cloud Optimized Geotiffs for other layers in SFMS Insights and we should do the same for snow coverage.

**Acceptance Criteria**
- [ ] Modify viirs_snow job to produce a COG instead of a pmtiles file
- [ ] Display this COG in SFMS Insights

**Additional context**
- Add any other context about the task here.
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Start with the viirs_snow job and the existing SFMS Insights map-layer handling. Trace how snow coverage currently produces and displays the pmtiles file, then confirm completion when the job produces a COG and SFMS Insights displays that COG instead.

Written by the indexing model from the issue text.