[mbed-tls] 3.0 Proposal: remove 3DES ciphersuites

Hi all,

We'd like to completely remove support for 3DES TLS ciphersuites in Mbed TLS 3.0. Those ciphersuites are vulnerable to the Sweet32 attack and 3DES has been deprecated by NIST.

If we remove them from Mbed TLS 3.0, they will remain available in Mbed TLS 2.16 and 2.x, the latter being supported until 3 years after 3.0 has been released.

As usual, if for any reason you need support for 3DES TLS ciphersuites in Mbed TLS 3.0, please speak up now and let use know about your use case!

More context can be found at https://github.com/ARMmbed/mbedtls/issues/4367

Regards, Manuel.