* Revert "Revert "openssl_csr: Allow to use cryptography as backend (#50324)""
This reverts commit bbd2e31e9f.
* Remove more complicated selection copy'n'pasted from openssl_privatekey.
* Add tests for backend selection.
* Add openssl_csr test for arbitrary string commonName.
* Allow to disable commonName -> SAN copying (fixes#36690).
* Allow to use cryptography as backend for openssl_csr.
* Use different curve.
* Adding changelog.
Includes changelog fragment for #49416, which didn't include one.