Hello qr code

Closes #144 (closed) and treats #9 (closed)

What does this MR do?

• Refactor PassportGenerator to gateway
• Remove qr code library
• Use tcpdf instead of fpdf library, that has better UTF8 support as well as qrcode generation support
• Adapt PassportGenerator and BusinessCard generators to tcpdf
• Do not use temporary files for businesscards, instead download businesscard directly

How confident are you it won't break things if deployed?

tests work

Links to related issues

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• joined #foodsharing-beta channel at https://slackin.yunity.org
• added an entry to CHANGELOG.md (description, merge request link, username(s))