Drop Kyber support

[dstebila]

With ML-KEM support now available in liboqs and also in other TLS implementations (open-quantum-safe/oqs-provider#561 (comment)), it's been suggested in open-quantum-safe/oqs-provider#561 (comment) that we drop Kyber support from liboqs and oqs-provider. Thoughts?

[dstebila]

In today's OQS status call, I suggested that we keep Kyber in the forthcoming liboqs 0.12.0 release, and then drop Kyber in 0.13.0. We would include a note in the 0.12.0 release notes warning that this is the last release with Kyber.

We also discussed the impact this has on oqs-provider, and specifically re-assigning TLS hybrid code-points to the reserved range (open-quantum-safe/oqs-provider#561). It seems convenient to do that re-assignment at the same time as dropping Kyber support.