Rework PRM Api access to fit the 1 request per second

[Grayknife]

• Implement a priority queue where requests to the API will be stored (mongodb)
• Implement a new worker:
  • The Worker conintously looks into the priority queue and fetches the next wanted request. It handles the requests and request limits (1 Request per Second). The worker will only handle the requests and store the results in another mongodb collection. Also it supports retries up to 3 times, but with lower priority.