Implement BIO.wanderN from Monix Task

[Avasil]

Please put the method in other companion objects as well (Task, UIO) with appropriate return type if it applies

General flow:

• Comment in this issue to let others know that someone is working on it
• Copy scaladoc and the implementation from Monix Task in similar place
• Modify signature to take advantage of typed errors if possible
• Implementation might require some changes, in most cases the compiler should guide you, also look for already ported operators for inspiration. The most common change is to use BiCallback instead of Callback to be able to signal errors on two different channels ("typed" channel and hidden channel for "fatal" errors).
• Copy the corresponding tests from Monix. Try to use BIO instead of Task with E different than Throwable when possible to uncover any possible bugs in the internals.
• If you test for a failure, try to test for both "expected" failure (error from E, it will be CancelableFuture(Left)) after runToFuture) and "fatal" failure (it will be a failed CancelableFuture).
• Take a look at the existing tests to see if there aren't any commented ones using newly implemented function and uncomment them.

Don't be shy to ping me if you need any advice or want to consult the solution. I really appreciate the involvement and I'm happy to help!

[pjurczenko]

I'll work on this one.