Add conversion methods for u256,b256 from tuple of u64s

[SwayStar123]

Description

Adds impl From<(u64, u64, u64, u64)> for u256, b256

Closes #5820

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[xunilrj]

My problem with this kind of conversions is endianess. As it is never clear which convention is being used and we always need to end up reading documentation.

Why not simple named conversions? Like from_be_words, from_le_words etc... or anything similar.

Also, it may also make sense to convert from and into arrays.

[SwayStar123]

My problem with this kind of conversions is endianess. As it is never clear which convention is being used and we always need to end up reading documentation.

Why not simple named conversions? Like from_be_words, from_le_words etc... or anything similar.

Also, it may also make sense to convert from and into arrays.

There are already array conversions for both endians in the std lib for u16, u32, u64, b256 and u256