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