Set default ciphers, set tls 1.2 via config, set curve prefs (#9315)

Config Checks at StartUp Part1

Config Checks; Tests for TLS Server

HSTS header implementation + tests

make gofmt happy with new go version...

make gofmt happy with new go version #2...

fix logic bug

fix typo

Fix unnecessary code block

config/default.json

@@ -7,6 +7,10 @@
         "ConnectionSecurity": "",
         "TLSCertFile": "",
         "TLSKeyFile": "",
+        "TLSMinVer": "1.2",
+        "TLSStrictTransport": false,
+        "TLSStrictTransportMaxAge": 63072000,
+        "TLSOverwriteCiphers": [],
         "UseLetsEncrypt": false,
         "LetsEncryptCertificateCacheFile": "./config/letsencrypt.cache",
         "Forward80To443": false,