Issue/2985 - Add asset with default cmaps (#3004)

* Allow changing color map during runtime

* Stary building asset with colormaps (currently using local files)

* Add option to invert the color maps

* Remove final use of local viridis file in example and fix broken cmap update

* Use synced resource for colormap files

* Update advanced colormapping example

* Apply suggestions from code review

Co-authored-by: Alexander Bock <alexander.bock@liu.se>

* Update data/assets/util/default_colormaps.asset

* Capitalize first letter of exported keys, to be more consistent with rest of code base

---------

Co-authored-by: Alexander Bock <alexander.bock@liu.se>

include/openspace/rendering/colormappingcomponent.h

@@ -70,11 +70,14 @@ public:
      */
     void initializeTexture();
 
+    void update(const dataloader::Dataset& dataset);
+
     static documentation::Documentation Documentation();
 
     glm::vec4 colorFromColorMap(float value) const;
 
     properties::BoolProperty enabled;
+    properties::BoolProperty invert;
     properties::OptionProperty dataColumn;
     properties::StringProperty colorMapFile;
     properties::Vec2Property valueRange;
@@ -110,6 +113,9 @@ private:
     bool _hasNanColorInAsset = false;
     bool _hasBelowRangeColorInAsset = false;
     bool _hasAboveRangeColorInAsset = false;
+
+    bool _colorMapFileIsDirty = true;
+    bool _colorMapTextureIsDirty = true;
 };
 
 } // namespace openspace