Another good candidate for publishing separately from Lighthouse is `sensitive_url` as it's a general utility crate and not related to Ethereum. This PR prepares it to be spun out into its own crate.
I've made the `full` field on `SensitiveUrl` private and instead provided an explicit getter called `.expose_full()`. It's a bit ugly for the diff but I prefer the explicit nature of the getter.
I've also added some extra tests and doc strings along with feature gating `Serialize` and `Deserialize` implementations behind the `serde` feature.
Co-Authored-By: Mac L <mjladson@pm.me>
