Tracking Disk usage in different modes

The last numbers were for blocks 709632 -> 834761
```
217M	./filters
2.7G	./utxos
 16M	./headers-inv
 12M	./headers
2.8G	./tweaks        33,679,543 tweaks 
1.7G	./tweak-index   54,737,510 tweaks
7.4G	.
```