Add an option to save group chat password
Spark could show a checkbox "Save password" below the password input field when joining a group chat and then it could save that password into spark.properties file encrypted, like it does for accounts. When trying to join the room it should do a check, if that room already has a password saved, decrypt it and automatically submit.
Applied Alexander's patch manually as https://github.com/igniterealtime/Spark/pull/163 (removed unneeded logger, fixed whitespace commits, fixed Save password checkbox, added comments).
Though i think this can be still improved as it currently opens and reads preferences file twice to get the room password and there is no way to remove the saved password other than deleting it from the preferences file.