dev: implement Into<bool,u256> trait

[enitrat]

which allows us to naturally do

let result:u256 = a.slt(b).into();

instead of

let result = if (a.slt(b)) {
            1
        } else {
            0
        };

[khaeljy]

@enitrat Can I do it?

[enitrat]

yes, please implement it under utils::traits

[khaeljy]

Perhaps we should implement Into<bool, u8> instead, which would allow conversion to any integer size?

BoolIntoU8::into(boolean_value).into()

[enitrat]

I said Into<bool,u32> so that we could directly push the values to the stack, but I meant Into<bool,u256>. of course we could do all integer types but we don't need it right now

we can already convert to felt but the shorter the better ;)