Blockedservers, more admin friendly and more

• Added Blockedservers.yml (in this file you can now block bungeecord subserver. If the user is on the server, he won't get any Verify Requests)
  Code improvments
  Switched to HikariCP as Connection Pool, there should be less errors
  Add more userfriendly debug messages (easier for me and for you)
  Add reward offline support

All files will now be transfered to the folder called DBVerifier, you can delete the old folder after starting the plugin once