Feat: unlock screen (WIP)

[rolznz]

TODO

• review storing the encryption key for checking in the http service
• is it ok that we only support the http usecase for now? - I think we can rely on standard PC unlock screen for Wails.
• review cookie structure
• return to previous URL functionality after logging in
• proper password check on startup
• setup page can currently be accessed if the app is running without a password - a malicious user could then change the node backend. I think this should be locked if the app is running
• prevent brute forcing passwords - currently rate limited at 1 request per second
• review general UX (start/unlock flow)