Docs site banner request for GitLab Plus survey

Survey banner request

Fill in the following information:

• What is the survey about? Please add a link for any related issues: I'm conducting research to learn about a number of different features for a future product offering called GitLab Plus (ux-research#1128 (closed)). This would be something specific to self-managed users, so we would like to target them through the Docs site.
• Survey text: Help us make decisions about new product features! [Take the survey.](https://gitlab.fra1.qualtrics.com/jfe/form/SV_3Idz5sSyEjKUWCW)
• Survey link: https://gitlab.fra1.qualtrics.com/jfe/form/SV_3Idz5sSyEjKUWCW
• Date to be published: Wednesday, January 12th
• Date to be unpublished: Thursday, January 13th