Add splice method to Bytes

[SwayStar123]

Description

Adds a splice method to bytes that lets you select start and end indices, and returns the range of bytes, removing them from the original bytes.

Checklist

• I have linked to any relevant issues.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation where relevant (API docs, the reference, and the Sway book).
  • If my change requires substantial documentation changes, I have requested support from the DevRel team
• I have added tests that prove my fix is effective or that my feature works.
• I have added (or requested a maintainer to add) the necessary Breaking* or New Feature labels where relevant.
• I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• I have requested a review from the relevant team or maintainers.

[K1-R1]

I like the addition of splice, but I think we should match Rust's Vec impl https://doc.rust-lang.org/std/vec/struct.Vec.html#method.splice by taking a second optional param replace_with