dasmap validity check

* check the validation token in DB based on all record hashes matches the calculated one
* the validation token to be generated in:
  - das_maps tool (connecting to mongodb directly)
  - and in create_das_js (which prepare dasmaps js file for mongo)
* load_maps will run more often if check_maps fail
* check_maps turned off in das_map tool (tools/das_mapping_db) as with short intervals it might interfare with the updates