feat: passcode lock in preferences (#644)

* feat: implement existing passcode lock in prefs

* chore: cleanup commented code and unused imports

* feat: improve design for passcode lock

* fix: propert folder naming

* feat: passcode lock form buttons margin

app/assets/javascripts/preferences/panes/security-segments/index.ts

@@ -0,0 +1,2 @@
+export * from './Encryption';
+export * from './PasscodeLock';