Make the testimonials into a carousel

[davidfischer]

The testimonials are in a carousel. There's a bunch of options but I made a few choices:

• I have it autoscrolling with the default 3s interval (we can force users to scroll manually or autoscroll at a different interval)
• We have buttons to scroll (these can be styled or removed)
• There's the dots at the bottom to indicate how many (this can be turned off)
• The width of scrolling items is configurable. I went with 75% of screen size at big screen sizes.

Before I start refactoring which testimonials to show, I wanted to get some feedback on this so far.

Screenshot

[ericholscher]

This seems like a reasonable approach. It lets us highlight the "best" one, and folks can scroll around if they want to see more. :+1:

I have it autoscrolling with the default 3s interval (we can force users to scroll manually or autoscroll at a different interval)

I'd probably increase this, or just make it manual scroll?

[davidfischer]

I'd probably increase this, or just make it manual scroll?

I just tested this with 1.5s and it was way too fast. However, I'll push a commit with the variable so we can customize it later if we want to.

[ericholscher]

I meant slower, not faster. But I think manual is probably the best option for now, since auto-advancing is pretty annoying if you're actually trying to read it.

[davidfischer]

I did a PR to make it manually scroll: https://github.com/readthedocs/ethicalads.io/pull/444