Add increment functionality to b256

[bitzoic]

Description

There are currently no mathematical operations allowed on a b256 in Sway. This should come with support of fuel-core v0.19.0 but for now we are able to add an increment function now.

This is critical functionality to storage optimizations that are in progress.

• Adds increment functionality to b256
• Moves and modifies overflowing add for u64 to the maths library
• Modifies the u128 and u256 libraries with new overflowing add

Closes #4781

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).
• 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.

[Braqzen]

utACK, mainly approving based on tests

[SwayStar123]

I dont see any tests for testing that the b256 doesnt overflow

[bitzoic]

I dont see any tests for testing that the b256 doesnt overflow

As far as I'm aware there is no #[should_panic] attribute for inline tests yet

[anton-trunov]

@bitzoic You can add it as an end-to-end test, perhaps. Those can expect panics

[IGI-111]

As we discussed, I think that b256 shouldn't have arithmetic operations, and that we should introduce a u256 primitive type instead to support those.

[bitzoic]

Closing in favor of #4794