Obscure secrets by default

[UppaJung]

1. DiceKeys, secrets derived from DiceKeys, and any other secrets should default to being obscured (hidden).
2. A single toggle switch should show/hide derived secrets on a page
3. State for showing/hiding secrets should be maintained between executions

Initially part of a request from Dan P.

1. when I unlock the DiceKey, don’t show the dice by default. I might just want to copy a password and I might be in a public place.
2. auto hide generated passwords but let me copy/paste them.

[johanbove]

The Android app is handling this right. The ios app (as of today) not yet, where the full DiceKey is displayed just to access the stored "secrets".