Adds a config file for cargo-deny[1] that runs the following checks:
* advisory-db[2] RUSTSEC checks for deps (like cargo-audit)
* errors if a dependency has been "yanked" from crates.io
* errors if attempting to use OpenSSL as a dependency.
The RUSTSEC checks copy over the whitelist from the current cargo-audit
config.
[1]: https://github.com/EmbarkStudios/cargo-deny
[2]: https://github.com/rustsec/advisory-db