Password protect identity in localstorage

The identity in local storage needs to be password protected.

Requirements:
* The password should be set on importing/creating an identity.
* The password should not be saved anywhere
* The password should only live in a temporary variable that unencrypts the identity in local storage, and the unencrypted identity only lives in a stateful variable. (aka, if you refresh the page, or the webapp reloads, you need to put in your password again)