Add checksum validation option

Under `General Options`, I would like to add an option to validate checksums for users who want to ignore possibly corrupted events.

`-V, --validate-checksums  Enable checksum validation`

This should be added to at least `csv-timeline` and `json-timeline`. If it is not too difficult, we can also add to the other commands that evtx files as well.

@fukusuket Could I ask you to do this one?