Add getPuased() function to getters

Created by: fbukevin

I notice that bull still provides function Queue.pause() to get tasks into state paused. But when I trying to look up tasks in a queue with bull-arena, I got an error:

WRONGTYPE Operation against a key holding the wrong kind of value

I check out this PR in bull-arena. The author modified in src/server/views/dashboard/index.js. However, after I modified, the new error occurred:

UnhandledPromiseRejectionWarning: TypeError: queue[(("get" + (intermediate value)) + "")] is not a function

bull-arena cannot map getPaused to function in bull.