Update readme preview video

[andrewtavis]

Terms

• [X] I have searched open and closed issues
• [X] I agree to follow activist's Code of Conduct

Issue

The video that we have on the readme is super out of date and reflects behaviors that would not be included in activist such as collecting phone numbers and other form entries. This issue has been known for some time, but focus has been on other places. It would be good to update this with more up to date versions from the designs.

[andrewtavis]

• Note that this is blocked by the revamp of the colors/designs in #215 :) Once that's done I'll redo some previews.

[andrewtavis]

Considering this right now, it might be better if we update this with a video of the actual platform rather than spending the time to make one of the designs :)