Create an script to detect bugs with the KeyValues to monitor not reported releay

After legacy/trac#28547 (moved) is solved, there will be KeyValues in the bandwidth file that can help to find bugs in sbws. And after legacy/trac#21377 (moved) is solved, anyone will be able to see the bandwidth files. There should be an script that can automatically detect these bugs. This is partly documented in https://pad.riseup.net/p/sbws-exclude-reasons-keep. The script should probably be in other package/component so that anyone can run it. Assigning for now to sbws component since depends on sbws.