Host regex volume chooser for WALs

There is a need to allow one to tie the volumes for sets of tservers to a specific volume. This is especially useful if one wants to tie the WALs to a specific volume for performance or space purposes. I suggest that we create a HostRegexVolumeChooser that can choose a volume based on the tserver hostname. So given the following configuration:
```
general.volume.chooser=org.apache.accumulo.server.fs.PerTableVolumeChooser
general.custom.volume.chooser.logger=org.apache.accumulo.server.fs.HostRegexVolumeChooser
```
We might create the following configuration
```
general.custom.volume.chooser.hostgroup.A=host[0-4]
general.custom.volume.chooser.hostgroup.A.volumes=hdfs://cluster1/accumulo
general.custom.volume.chooser.hostgroup.B=host[5-9]
general.custom.volume.chooser.hostgroup.B.volumes=hdfs://cluster2/accumulo
```
This will tie the WALs for host group A to volume1 and the WALs for host group B to volume2

Start by reviewing the existing PerTableVolumeChooser and the volume chooser configuration shown in the issue, then compare them with the proposed HostRegexVolumeChooser settings. Confirm how host groups should match tserver hostnames and how WAL volume selection should behave; done means the example configurations reliably route each host group to its specified volume.

Written by the indexing model from the issue text.