Add FCS and non FCS functions

* [ ] `SlicedPacket::from_ethernet_with_fcs`
* [ ] `SlicedPacket::from_ethernet_without_fcs`
* [ ] Update `SlicedPacket::from_ethernet` to auto detect FCS
* [ ] `LaxSlicedPacket::from_ethernet_with_fcs`
* [ ] `LaxSlicedPacket::from_ethernet_without_fcs`
* [ ] Update `LaxSlicedPacket::from_ethernet` to auto detect FCS