This entails: * Surface a notification for existing Sync users that a new Sync Key has been generated from their old Sync Key/passphrase. They don't need to do anything on their other machines, but their old Sync Key/passphrase is no longer valid. * The account creation wizard won't allow you to set a custom passphrase, it just shows a generated one. * The My Sync Key dialog no longer allows you to set a custom passphrase, it just allows you to generate a new one. * Everywhere Sync Keys are shown and entered we need to aid the user with hyphens. The hyphenation/dehyphenation should happen in Weave.Util.* helpers, the UI code shouldn't have to know about specific Sync Key formats.
Since we're ripping out custom passphrases we can also rip out the whole Sync Key strength meter thingie. Yay!
Created attachment 493479 [details] [diff] [review] v1
verified with recent nightly builds