* slots: create primitives crate for consensus slots
* offences: add method to check if an offence is unknown
* babe: initial equivocation reporting implementation
* babe: organize imports
* babe: working equivocation reporting
* babe: add slot number to equivocation proof
* session: move duplicate traits to session primitives
* babe: move equivocation stuff to its own file
* offences: fix test
* session: don't have primitives depend on frame_support
* babe: use opaque type for key owner proof
* babe: cleanup client equivocation reporting
* babe: cleanup equivocation code in pallet
* babe: allow sending signed equivocation reports
* node: fix compilation
* fix test compilation
* babe: return bool on check_equivocation_proof
* babe: add test for equivocation reporting
* babe: add more tests
* babe: add test for validate unsigned
* babe: take slot number in generate_key_ownership_proof API
* babe: add benchmark for equivocation proof checking
* session: add benchmark for membership proof checking
* offences: fix babe benchmark
* babe: add weights based on benchmark results
* babe: adjust weights after benchmarking on reference hardware
* babe: reorder checks in check_and_report_equivocation