Permissions persist across logins, across users

[dghelm]

Describe the bug

A user can logout, login with a new seed, and if permissions were already granted for a domain+dataDomain pairing, they won't be requested of the new user.

To Reproduce

1. Visit https://300ajmf6mc3fv6me8sihbj12k9rqttk78uingfans524secs9267n58.siasky.net/
2. Logout if logged in.
3. Authenticate, use Sign Up, approve permissions.
4. Log Out
5. Authenticate, use Sign Up.
6. No prompt for permissions.

Expected behavior

Same as above, but step 6 sees a prompt for permissions.

Additional context

We need to either delete local indexedDB, or have a new indexedDB name per user logging in. Later versions should encrypt or obfuscate this data if it persists on the browser after logging out.