Elevation not used in calculations

[ArrEssJay]

Sun and moon positions are (to a greater or lesser extent) dependent on elevation as well as latitude/longitude. The suncalc library used accepts an optional height parameter, defaulting to the geodetic surface.

It would be useful if this plugin could additionally store and use an elevation parameter (or estimate it from an elevation model) for more accurate calculations.

[fetzerch]

Remark: suncalc only supports this in getTimes (which is currently only used for annotations). The request to add support also to getPosition: mourner/suncalc#141 is still open.