Add multiple dataset versions

Add versioning to view multiple versions of a dataset:

• Backend updates:

  • index datasets in elasticsearch with index names datasetkey-version and datasetkey-groups-version
  • tiles directory structure is changed to contain dataset version as tiles/datasetkey/version/...
  • bitmaps directory structure is changed to contain dataset version as bitmaps/datasetkey/version/...

• Frontend updates:

  • update dataset model to add versions array and current for selected version of dataset
  • Fix routing on angular side, now dataset path is defined as /map/key/version
  • Add version dropdown to map dashboard view
  • Default version is set as latest which redirects to the latest indexed version of the dataset
  • Update map history to keep history for dataset key and dataset version
  • Add popper.js to scripts before bootstrap to make dropdown work correctly

cartolab-frontend/src/app/core/about/about.component.spec.ts

@@ -63,10 +63,12 @@ describe('AboutComponent', () => {
       (<jasmine.Spy>datasetService.getDatasetStats).calls.reset();
     });
 
-    it('should get the stats from the datasetService', () => {
+  it('should get the stats from the datasetService', () => {
       component.selectDataset(datasets[0]);
-      expect(datasetService.getDatasetStats).toHaveBeenCalledWith(datasets[0].key);
-    });
+      expect(datasetService.getDatasetStats).toHaveBeenCalledWith(
+	    datasets[0].key, datasets[0].current
+      );
+  });
 
     it('should compute the total from the stats', () => {
       const stats = { articles: 12, authors: 15, teams: 2 };