RSA: properly generate algorithm identifier for RSA-PSS signatures

RSA: properly generate algorithm identifier for RSA-PSS signatures

Fixes #13969

- properly handle the mandatory RSA-PSS key parameters
- improve parameter checking when setting the parameters
- compute the algorithm id at the time it is requested so it
  reflects the actual parameters set
- when generating keys do not override previously set parameters
  with defaults
- tests added to the test_req recipe that should cover the PSS signature
  handling

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/13988)