factor: only supports numbers up to 2^128 - 1 reliably with num_prime crate

This issue is similar to https://github.com/uutils/coreutils/issues/1559, except that at the time of factor's implementation currently, u128 digit should be supported without issues using num_prime crate. The numbers that aren't supported reliably is anything above u128. For example, the factor implementation we have fails for 340282366920938463463374607431768211456768211458:

$ ~/coding-project/coreutils/target/release/factor 340282366920938463463374607431768211456768211458
factor: Factorization incomplete. Remainders exists.

On GNU, we see the following results:

$ factor 340282366920938463463374607431768211456768211458
340282366920938463463374607431768211456768211458: 2 11 11 2875070119 2895113854549549 168931247951478372779

It's true that GNU being compiled with GMP allows this factorization to be performed (otherwise, you get factor: ‘340282366920938463463374607431768211456768211458’ is too large ), but if we want to support this within uutils' factor, we might want to figure out how to get the num_prime crate to work reliably and correctly with >u128 digits or use something else entirely.

Start with the existing factor implementation and its use of the num_prime crate. Reproduce the reported input and compare its output with GNU factor, then investigate whether num_prime can reliably handle values above u128 or whether another approach is needed. Done means factorization no longer reports an incomplete remainder for supported values above u128.