Remove `DES-CBC3-SHA` from TLS Ciphers

[boscard]

I've scanned one of my setup lately and nmap is reporting use of unsecure cipher:

nmap -Pn -p 443 --script ssl-enum-ciphers my.dev.setup.com
 Starting Nmap 7.95 ( https://nmap.org ) at 2025-06-12 15:40 PDT
 Nmap scan report for my.dev.setup.com (1.2.3.4)
 Host is up (0.69s latency).
 
 PORT    STATE SERVICE
 443/tcp open  https
 | ssl-enum-ciphers:
 |   TLSv1.2:
 |     ciphers:
 |       TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (ecdh_x25519) - A
 |       TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (ecdh_x25519) - A
 |       TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 (ecdh_x25519) - A
 |       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (ecdh_x25519) - A
 |       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (ecdh_x25519) - A
 |       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 (ecdh_x25519) - A
 |       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (ecdh_x25519) - A
 |       TLS_RSA_WITH_AES_128_GCM_SHA256 (rsa 2048) - A
 |       TLS_RSA_WITH_AES_256_GCM_SHA384 (rsa 2048) - A
 |       TLS_RSA_WITH_AES_128_CBC_SHA256 (rsa 2048) - A
 |       TLS_RSA_WITH_AES_256_CBC_SHA256 (rsa 2048) - A
 |       TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
 |       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
 |       TLS_RSA_WITH_3DES_EDE_CBC_SHA (rsa 2048) - C
 |     compressors:
 |       NULL
 |     cipher preference: server
 |     warnings:
 |       64-bit block cipher 3DES vulnerable to SWEET32 attack
 |   TLSv1.3:
 |     ciphers:
 |       TLS_AKE_WITH_AES_256_GCM_SHA384 (ecdh_x25519) - A
 |       TLS_AKE_WITH_CHACHA20_POLY1305_SHA256 (ecdh_x25519) - A
 |       TLS_AKE_WITH_AES_128_GCM_SHA256 (ecdh_x25519) - A
 |     cipher preference: server
 |_  least strength: C

Is there any specific reason that ApiSix has to use 3DES? Can this be removed?

I have prepared a PR covering this and also adding easy way to configure list of supported ciphers by ApiSix #834 - maybe this could be merged?

[bzp2010]

@boscard Thanks for your contributions.

It seems some documentation is missing in this PR.

https://github.com/apache/apisix-helm-chart/actions/runs/15642404816/job/45773110189?pr=834

Use make helm-docs to fix this and commit the changes and I think it will work. After that we can merge it.

I am positive about this PR work.

[boscard]

@bzp2010 Thank you very much for checking my PR and pointing me to missing parts.
I have updated docs as you asked. Could you check again and let me know if there is still missing anything?