Fix #815: Allow use without cookies, Add a global notice popup system

Exactly what it says in the title. Previously if you disable cookies the site would not load at all at least on chromium. Now you can use the frontend, even login etc.

To make the alert good I ended up implementing a global notice system so that any code in the application can push an error, warning or info notice like this: const myNotice = dispatch('pushGlobalNotice', { messageKey: "some.i18n.key", messageArgs: ['possible args for i18n string'], timeout: 5000, level: 'error') and dispatch('removeGlobalNotice', myNotice). I hope not allowing messages to be pushed without i18n helps in the long run.

Note: pics don't reflect the actual case of what happens without cookies, I added the warning and info just as a test

on mobile on breezy light (testing args as well)