Add Disk Utilization and FS Listings with Sizes to `consul debug`

### Feature Description

We should add host information about data directory utilization to the `consul debug` information that is collected. In particular it would be useful to collect information about:

1. How full the disk is
2. How many files are in the data directory and subdirectories.
3. The sizes of those files in the data directory.

Disk utilization metrics could be tricky but listing files with sizes should be easy enough to accomplish by walking the data directory and getting the size of each file.