Figure out Hadoop version compatibility

The 5.x-HBase-2.0 branch is presently incompatible with both Hadoop 2.7 and Hadoop 3.0.

This stems from PhoenixMetricsSink and LoggingSink both of which extend MetricsSink from Hadoop. Hadoop leaks a commons-configuration class into a method signature and changes the dependency across versions.

This makes it extremely annoying to work around downstream (we would have to create multiple maven modules to shim around this). We should figure out what compatibility we want to have. Post PHOENIX-4405, it's only Hadoop3.