feature gate HotShot trait implementations in `espresso-types` crate

[imabdulbasit]

The espresso-types crate currently compiles everything, including the HotShot trait implementations, which brings in a significant number of dependencies. However, not all external crates may require the HotShot trait functionality. Some might only need the core types, without the HotShot trait implementations or the SeqTypes (which implements the Hotshot NodeType trait).

To address this, we should introduce a feature (e.g., full or hotshot-impls) that allows users to optionally compile the HotShot trait implementations. By default, these would be excluded unless the feature is explicitly enabled, reducing compilation time and dependencies for users who don’t need them.