Added support code for RSA and EC key encoding (including reconstruction of all public and private key elements from the private key structure), with raw and PKCS#8 formats, both in DER and PEM.
- [DH] inc/bearssl_ec.h
- [DH] inc/bearssl_pem.h
- [DH] inc/bearssl_rsa.h
- [DH] inc/bearssl_x509.h