remove sp_std dependency

Cargo.lock

Cargo.toml

docs/api/runtime-calls.md

docs/api/runtime-errors.md

docs/api/runtime-errors.po

pallets/authority-members/Cargo.toml

pallets/authority-members/src/lib.rs

pallets/certification/Cargo.toml

pallets/certification/src/lib.rs

pallets/certification/src/tests.rs

pallets/distance/Cargo.toml

pallets/distance/src/benchmarking.rs

pallets/distance/src/lib.rs

pallets/distance/src/median.rs

pallets/distance/src/mock.rs

pallets/duniter-account/Cargo.toml

pallets/duniter-account/src/lib.rs

pallets/duniter-test-parameters/Cargo.toml

pallets/duniter-wot/Cargo.toml

pallets/duniter-wot/src/lib.rs