Update test.openquantumsafe.org & resolve some issues

[bhess]

Updates the build for test.openquantumsafe.org:

• Updates oqs-provider to 0.5.1

Fixes a few issues:

• ssl groups for OQS-kems were not correctly resolved to strings.

Example:

/curl -v --cacert cert.pem --curves x25519_kyber512:kyber768 https://test.openquantumsafe.org:6245/
...
Client-side KEM algorithm(s) indicated:
0x2f39:0x023c

The update resolves them correctly:

/curl -v --cacert cert.pem --curves x25519_kyber512:kyber768 https://test.openquantumsafe.org:6245/
...
Client-side KEM algorithm(s) indicated:
x25519_kyber512:kyber768

-> needed to patch nginx to use SSL_group_to_name instead OBJ_nid2sn when using OpenSSL >= 3.0.

• signature/kem response was not available with the ports that offer the default groups. Example:
  https://test.openquantumsafe.org:6043 returned Successfully connected using !. With the update it returns Successfully connected using rsa3072-x25519!

-> updated interop.conf to not hardcode the negotiated group in the response html but instead use nginx's $ssl_curve variable available from v1.21.5. Also needed to patch nginx to correctly resolve the string when using OpenSSL >= 3.0.

• server html response was malformed (missing </html> tag)

The update is already applied to https://test.openquantumsafe.org.
May see if there is interest in nginx upstream to apply the patch there.

[baentsch]

LGTM. Thanks for the improvements.