Feature (v1): add latest handshake data to API response (#203)

* feature: updated handshake-related fields type

* feature: updated handshake representations in templates

* feature: added handshake field to Swagger schema

internal/server/docs/docs.go

@@ -1512,6 +1512,9 @@ const docTemplate = `{
                 "IgnoreGlobalSettings": {
                     "type": "boolean"
                 },
+                "LastHandshakeTime": {
+                    "type": "string"
+                },
                 "Mtu": {
                     "description": "Global Device Settings (can be ignored, only make sense if device is in server mode)",
                     "type": "integer",

internal/server/server.go

@@ -128,6 +128,7 @@ func (s *Server) Setup(ctx context.Context) error {
 	s.server.Use(sessions.Sessions("authsession", cookieStore))
 	s.server.SetFuncMap(template.FuncMap{
 		"formatDate":  common.FormatDateHTML,
+		"formatTime":  common.FormatToUnixTime,
 		"formatBytes": common.ByteCountSI,
 		"urlEncode":   url.QueryEscape,
 		"startsWith":  strings.HasPrefix,