[Optical] Do not use SNAP

[remi-braun]

Sentinel-3

Do not geocode S3 data with SNAP, to remove this dependency for optical data.

Reproject

⚠️ Geocoding is not as simple as initially thought

The goal is to apply lon/lat/alt arrays to every rasters (maybe through GCPs ? or -geoloc in gdalwarp ?)

Take a look at the ongoing @rioxarray #329 discussion.
And maybe at this thread

This solution using gdal warp -geoloc (script) exists (from this thread and this gdal documentation) but uses gdal CLI, which is not really wanted...

Rad2Refl

rad2refl: here

    public static float radianceToReflectance(float rad, float sza, float e0) {
        return (float) ((rad * Math.PI) / (e0 * Math.cos(sza * RAD_PER_DEG)));
    }