Add defaultValue to URL

[andra961]

Following #842, I think a cool feature would be to update the URL with the defaultValue when clearOnDefault is false (or by through some other option):

const [search] = useQueryState('param', { defaultValue: 'default', clearOnDefault: false });

would result in:

http://xyz.com?param=default

I think it would be useful since the default value could depend on many factors and thus be different from user to user, but if added to the URL it would always be shareable at any time.

[stychu]

I also expected this to be a feature but unfortunately atm its not and you have to manually handle setting default value via useEffect.