Adding ability to serve TLS directly from Mattermost server (#4119)

config/config.json

@@ -2,6 +2,14 @@
     "ServiceSettings": {
         "SiteURL": "",
         "ListenAddress": ":8065",
+        "ConnectionSecurity": "",
+        "TLSCertFile": "",
+        "TLSKeyFile": "",
+        "UseLetsEncrypt": false,
+        "LetsEncryptCertificateCacheFile": "./config/letsencrypt.cache",
+        "Forward80To443": false,
+        "ReadTimeout": 30,
+        "WriteTimeout": 60,
         "MaximumLoginAttempts": 10,
         "SegmentDeveloperKey": "",
         "GoogleDeveloperKey": "",
@@ -231,4 +239,4 @@
         "TurnUsername": "",
         "TurnSharedKey": ""
     }
-}
+}