Improve stats reporting by disabling in-kernel UDP checksum validation

[ibaldin]

Per this article, we can disable UDP checksum validation in the kernel so E2SAR can see bad UDP packets:

https://linux-tips.com/t/how-to-disable-udp-checksum-control-in-kernel/362

We can implement this as an option and add additional error reporting for bad UDP packets (which otherwise will never reach E2SAR and cannot be reported).