Make support mail contact configurable

Still fails because the config is not available in the base template.

config/config.go

@@ -46,6 +46,7 @@ type Config struct {
 		SmtpUseAuth  bool          // Set whether to use authentication on the smarthosthost
 		SmtpIdentity string        // Smarthost username
 		SmtpPassword string        // Smarthost password
+		SupportMail  string        // separate mail address for support contact
 	}
 	SQL struct {
 		Type          string // Can be "SQLite" or "Mysql"
@@ -143,6 +144,15 @@ func validateConfig(conf *Config) error {
 		err = fmt.Errorf("Validating config: Mail FromName could not be parsed (%w)", mailFromNameErr)
 		log.Println(err)
 	}
+	supportMail, mailSupportMailErr := mail.ParseAddress(string(conf.Mailer.SupportMail))
+	if !(mailSupportMailErr == nil) {
+		err = fmt.Errorf("Validating config: SupportMail could not be parsed (%w)", mailSupportMailErr)
+		log.Println(err)
+	}
+	if !(supportMail.Name == "") {
+		err = fmt.Errorf("Validating config: SupportMail must not contain a name")
+		log.Println(err)
+	}
 	if !(conf.SQL.Type == "SQLite" || conf.SQL.Type == "Mysql") {
 		err = fmt.Errorf("Validating config: SQL type must be 'SQLite' or 'Mysql', but is '%s'.", conf.SQL.Type)
 		log.Println(err.Error())

config/config.json

@@ -28,7 +28,8 @@
 		"smtpPort": 25,
 		"smtpUseAuth": false,
 		"smtpIdentity": "",
-		"smtpPassword": ""
+		"smtpPassword": "",
+		"supportMail": "officeHoursSupport@localhost"
 	},
 	"SQL": {
 		"type": "SQLite",