Add new security policy (20250211)

[Mark-Simulacrum]

Release Summary:

n/a (probably?)

Resolved issues:

n/a

Description of changes:

This PR adds a new security policy that is similar/mix of default_tls13 and rfc9115, but with a minimum protocol support of TLS 1.3. As tested, it is compatible with default_tls13 and rfc9115, making it a middle ground for migration towards rfc9115.

Call-outs:

n/a

Testing:

Added a unit test verifying the compatibility -- I'm hoping it runs in CI since locally I think I don't have TLS 1.3 support for it to run successfully.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[Mark-Simulacrum]

2nd commit adds a new cert with a sha384/p-384 key which is compatible with rfc9151.... I can switch that to using the permutations certificate+key (under tests/pems/permutations/ec_ecdsa_p384_sha384) if that's preferred.