Update Scalability test

[It was suggested](https://github.com/apache/accumulo-testing/pull/151#issuecomment-916971084) that the scalability test be run and updated. After a bit of investigation it seems like there is a lot that has changed since the test was in working order and subsequently may take a bit of work to get it in a usable state again.

Before I put too much work into it wanted to make a ticket to see if anyone has an opinion whether this test is still useful and would be worth reviving.