- Removed the constructor taking a (n, d, e) tuple and moved
it to `RSAPrivateKey`
- Removed default constructor with key generation because it was always
misused and the default key size is quite small
- Added utility constructors to accept a key pair, public key, private
key or both
- Made constructor parameters const
- Updated test to use generated random keys where possible
The decoding inside `RSA::parse_rsa_key` is quite complex because it
tries to understand if it's decoding PKCS#8 or PKCS#1. Simplify the code
by moving the burden to the PEM decoder.
Add support for encoding parameters in `wrap_in_private_key_info` and
`wrap_in_subject_public_key_info` as well as turn `Span<int>` into
`Span<int const>`.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
