[FIXS V1.1 RC2] Enhance feature comparison between TLS 1.2 and TLS 1.3

[kleihan]

Provided by Li Zhu:

Protocol Features (https://www.fixtrading.org/standards/fixs-online/#protocol-features)
This part compares TLS 1.3 with TLS 1.2. But the list is far from complete. From the view of security, TLS 1.3 has made significant improvements over TLS 1.2, rules out many insecure or obsolete algorithms, and most significantly uses AEAD algorithms only. As a guide, we had better incorporate this information into our guide. The information can be found in section 1.2 of RFC 8446. The FIXS Appendix is recommended to be changed, at least to make it clear that in Section 5.3 of Appendix A (List of recommended cipher suites), CBC mode should be used with caution.