add constellation visualization

Author: ZhifengHan1101

.idea/.gitignore

@@ -36,6 +36,22 @@ def main():
     KITS_TEST_CASES.kits_test_cases()
     print("END.")
 
+    """
+    The visualization results generated here will be located under 
+    /StarPerf_Simulator/visualization/CesiumApp. Before you uncomment 
+    this section and run the visualization, please make sure to set your 
+    own Cesium Token by assigning it to the Cesium.Ion.defaultAccessToken 
+    parameter in /StarPerf_Simulator/visualization/html_head_tail/head.html
+    
+    For the specific steps of rendering the resulting web page, please 
+    refer to the Constellation Visualization Instructions in README.md.
+    """
+    # print("Starting constellation visualization...")
+    # # test visualization part in "visualization/" in starperf 2.0
+    # import visualization.constellation_visualization as CONS_VIS_TEST_CASES
+    # CONS_VIS_TEST_CASES.visualization_example()
+    # print("END.")
+
     """
     This will test the functionality of duration constellation. It is similar to the previously 
     implemented XML Constellation, but supports customizing the simulation time and simulation