Force TLS 1.2+

[2rs2ts]

I would like a way to force kiam-server to only accept TLS 1.2+. This is a security requirement at my company.

[2rs2ts]

Not quite the same request but I am certain it will touch the same code. We should also be able to block CBC ciphers, since they're known to be vulnerable https://docs.microsoft.com/en-us/dotnet/standard/security/vulnerabilities-cbc-mode