Add stricter lint levels to all crates & test on all features in CI

[emostov]

Each crate should have

#![forbid(unsafe_code)]
#![deny(clippy::all, clippy::cargo, missing_docs, clippy::pedantic)]

Although we should watch out for clippy::pendantic adding too many false positives.

In CI we should make sure to run

cargo clippy --all-targets --all-features -- -D warnings