Ernst animate non rain

To accommodate the 'zettingsvloeiingsproef' we need to be able to add other-than-rain dynamic rasters.

- [x] Prevent bug with setting opacity on non-existent leaflet-overlays
- [x] Add leaflet overlays when dynamic raster in hash
- [x] Only request rcc with aggwindow when rain
- [x] Include layer slug in `RasterService.rasterInfo()`
- [x] Enable line graph with time on the x-axis
- [x] Only request intensity data when rain
- [x] Create default wms styles when not elevation or landuse
- [x] Add *westerschelde* to raster info
- [x] Add line graph to pointObject template for dynamic rasters that do not contain rain