Disable show_password_hint by default

A setting that provides unauthenticated access to potentially sensitive data
shouldn't be enabled by default.

.env.template

@@ -210,8 +210,10 @@
 ## The change only applies when the password is changed
 # PASSWORD_ITERATIONS=100000
 
-## Whether password hint should be sent into the error response when the client request it
-# SHOW_PASSWORD_HINT=true
+## Controls whether a password hint should be shown directly in the web page if
+## SMTP service is not configured. Not recommended for publicly-accessible instances
+## as this provides unauthenticated access to potentially sensitive data.
+# SHOW_PASSWORD_HINT=false
 
 ## Domain settings
 ## The domain must match the address from where you access the server