Add GDPR / cookie acceptance modal

[mihow]

See discussion in #338

[joseepoirier]

@annavik How can I help here?

[annavik]

Sorry I just assigned you, I planned to write a comment 😅 I think defining the content and logic for this task is a privacy policy matter. I wonder if we could get some help defining this?

Questions:

• What should the cookie consent popup say?
• What options should we present in the cookie consent popup ("allow all", "allow necessary", etc.)?
• What effect should the different cookie consent options have on tracking and other cookies?
• Do we need to define a privacy policy?

[joseepoirier]

Contacted Mila's Legal/Compliance team for support.