ensure zupass works on sunmi device

[ichub]

proposal

• new frontend app in the repo
• 1st screen - enter email + ticket secret + store in localstorage
• calls a new route on the backend that verifies that these credentials are valid
• if they are valid, takes you to a scan screen, if they are invalid, takes you to the login page again
• when a ticket is scanned, this app uses the ticket secret as its 'auth token'/'proof'

integrating with the device

• when a qr code is scanned, what does the sunmi device actually do? my assumption is that it communicates the content of what it scanned to the running application using the keyboard.
• todo: figure out what it actually does
• todo: make sure that the scan screen can accept input from the sunmi device.

implementation strategy

• don't implement this all in one go
• start with figuring out what the sunmi device does when it scans a qr code / barcode.
• build a frontend app that has literally no functionality apart from rendering hello world, and deploy that to a personal staging branch, and make sure that it renders on the device
• build the checkin flow first
• build the login flow last

to think about

• how to communicate this to volunteers
• when to communicate it
• think about potential exceptional cases, eg. some device gets logged out in the middle of the event
• how to get all the correct devices logged in (what is the setup of the coworking space)
• confirm device correctness

once this is implemented, perform a test with someone on the devconnect side

[rrrliu]

Update: Zupass login, scanning with a camera, and checking in work on the device per Ligi's comments. We can replace this task with #954 and #955