This extends `do_settings_change` function for parameters like
`success` and `error` functions which will replace the default ones,
for functions that need to be excuted in success callbacks and for
desired success message.
All these parameters are optional.
We have some settings which are inter-dependent. If one setting
is checked or unchecked, it's dependent-sub-setting get disabled
or enabled. i.e. If user unchecked setting allow-message-editing
then message-editing-time-limit setting should get disabled in UI.
Add generic function to change disable attribute of sub settings
on checked or unchecked event of main setting in `settings_ui.js`.
