Intro: how to generate API token

[billaltermatt]

In the introduction of the documentation, you provide a link to Qualtrics' API documentation (https://api.qualtrics.com/) but it may be more helpful for new users if they had a direct link to Qualtrics' instructions on how to generate an API token: https://www.qualtrics.com/support/integrations/api-integration/overview/#GeneratingAnAPIToken

[juliasilge]

We can try this again, but Qualtrics moves these URLs around pretty frequently and we have had to update them a lot. There are rules on CRAN about how included URLs are allowed to forward so it was a bit of whack-a-mole. Maybe we should give it another go!