num-prime 0.4.0

Generic and optimized primality test, factorization and various number theoretic functions with arbitrary precision based on `num`.
Documentation
# Roadmap for v0.next
- Implement SIQS
- Euler totient
- support `primal` as backend

# Roadmap for v1
- Support modular integer in a unified API
- Stablize API, determine minimal verison for each dependency
- Support no_std
- Split the nt_funcs, factor and primality modules into sub files, and put the tables into the related files.

# Undetermined
- Use NumAssign as trait bounds and see if there's prominent performance improvement
- Support `rug` and `ibig` as backend
- Support `rug` & `primal` or `primesieve-sys` as PrimeBuffer backend
- Support async and multi-thread
- Implement factorization for Gaussian integers (and other quadratic integers?)

# Not in plan
- Support number field sieve factorization (this is efficient only for very larg numbers)