Add CI, upgrade bindgen, fix formatting and clippy

[arctic-alpaca]

• Adds CI: just basic clippy and formatting checks with a bit of caching to reduce CI wait time.
• Upgrades bindgen: this got rid of a few clippy issues and results in formatted bindings.
  • With this, I also updated pregenerated.rs.
  • Formatting normalizes doc comments now.
• Fixes multiple clippy warnings.
• The feature check did short circuit if both features where active, this now errors out properly.