clean up error messages and namings

pallets/certification/src/benchmarking.rs

pallets/certification/src/lib.rs

pallets/certification/src/weights.rs

pallets/distance/src/lib.rs

pallets/distance/src/tests.rs

pallets/duniter-wot/src/lib.rs

pallets/duniter-wot/src/mock.rs

pallets/membership/src/lib.rs

pallets/membership/src/mock.rs

primitives/membership/src/traits.rs

runtime/common/src/pallets_config.rs

runtime/common/src/weights/pallet_certification.rs

runtime/common/src/weights/pallet_identity.rs