Add a yielding filter

It seems like a yielding filter would be useful to add to Accumulo. Could add an option like `yield.time` to the existing filter base class. The downside of adding an option to the existing class is that it may conflict with user filter options. Could also create a new class, but that option would not benefit existing implementations of Filter.

Below is a link to a yielding filter I created for performance testing for apache/accumulo-testing#56

[YieldingFilter.java](https://github.com/apache/accumulo-testing/blob/71a788e8c94e0e2e1b7afcfc98b8bb7797d00504/src/main/java/org/apache/accumulo/testing/performance/tests/YieldingFilter.java)

Start with the linked YieldingFilter.java performance-test implementation and the existing filter base class in Accumulo. Compare the two approaches while investigating the stated risk that a yield.time option could conflict with user filter options. Done requires an agreed choice between extending the base class and adding a new class, with the behavior and compatibility expectations defined.

Written by the indexing model from the issue text.