Implement qr-scanner and pages using it in svelte

[PeterJFB]

What has been added?

• A scanner implemented with svelte store 😍
  • A component can listen by calling cardKeyScanStore.subscribe, or using $-syntax
  • Works similarly to the previous one, except that iv'e ensured that only one "setTimeout"-loop is created (regardless of how many listens to the event), such that its behavior becomes way more consistent.
• Two pages, /qr (create user by scanning card), and /activate_user (make users active/inactive)
  • The other moderator-pages are almost finished, and will come in a separate pr

Additional changes

• Bumped crypto-random-string and mongoose
• Created userApi for calling /user-endpoint
• Added types for serialport and web-nfc

Mayb-confusing-svelte-things

• Moved /qr and /activate_user to a (userCardKey)-folder, which allows me to create a script-file which runs a single time when a user enters these pages: (userCardKey)/+layout.svelte
• A writable svelte store is deleted whenever it has 0 subscribers, which is why (userCardKey)/+layout.svelte subscribes to it even though it does not use it

[eikhr]

Can't say I understood all the card reader code, but it looks good:)
svelte/store looks super nice!